Python_final_print_vison_academy_9822506209.pdf

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Python Notes
http://www.visionacademe.com
History: Python is a widely used general-purpose, high level programming scripting
language. It was created by Guido van Rossum in 1991
Q.Python Features
1) Easy to Learn and Use
Python is easy to learn as compared to other programming languages. Its syntax is
straightforward and much the same as the English language. There is no use of the semicolon
or curly-bracket, the indentation defines the code block. It is the recommended programming
language for beginners.
2) Interpreted Language
Python is an interpreted language; it means the Python program is executed one line at a time.
The advantage of being interpreted language, it makes debugging easy and portable.
3) Cross-platform Language
Python can run equally on different platforms such as Windows, Linux, UNIX, and Macintosh,
etc. So, we can say that Python is a portable language. It enables programmers to develop the
software for several competing platforms by writing a program only once
4) Free and Open Source
Python is freely available for everyone. It is freely available on its official
website www.python.org.
5) Object-Oriented Language
Python supports object-oriented language and concepts of classes and objects come into
existence. It supports inheritance, polymorphism, and encapsulation, etc. The object-oriented
procedure helps to programmer to write reusable code and develop applications in less code.
6) GUI Programming Support
Graphical User Interface is used for the developing Desktop application. PyQT5, Tkinter, Kivy
are the libraries which are used for developing the web application
7) Dynamic Memory Allocation

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Python Notes
In Python, we don't need to specify the data-type of the variable. When we assign some value
to the variable, it automatically allocates the memory to the variable at run time. Suppose we
are assigned integer value 15 to x, then we don't need to write int x = 15. Just write x = 15.
8) Embeddable
The code of the other programming language can use in the Python source code. It can use
Python source code in another programming language as well.
Q.Comparing C,C++,Python
C C++ Python
C was developed by
Dennis Ritchie between
the year 1969 and 1973 at
AT&T Bell Labs.
C++ was developed by
Bjarne Stroustrup in
1979.
Python was created by Guido
van Rossum, and released in
1991.
More difficult to write
code in contrast to both
Python and C++ due to
complex syntax.
C++ code is less complex
than C but more complex
in contrast to python. Easier to write code.
Longer lines of code as
compared to python.
Longer lines of code as
compared to python.
3-5 times shorter than
equivalent C/C++ programs.
Variables are declared in
C.
Variables are declared in
C++ Python has no declaration.
C is a compiled language.
C++ is a compiled
language.
Python is an interpreted
language.
C contains 32 keywords.
C++ contains 52
keywords. Python contains 33 keywords.
For the development of
code, C supports
procedural programming.
C++ is known as hybrid
language because C++
supports both procedural
Python supports multiple
programming paradigms,
including procedural, object-

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Python Notes
C C++ Python
and object oriented
programming paradigms.
oriented, and functional
programming.
C does not support
inheritance.
C++ support both single
and multiple inheritance
Python supports all 5 types of
inheritance i.e. single
inheritance, multiple
inheritance, multilevel
inheritance, hierarchical
inheritance, and hybrid
inheritance
C provides malloc() and
calloc() functions for
dynamic memory
allocation, and free() for
memory de-allocation.
C++ provides new
operator for memory
allocation and delete
operator for memory de-
allocation.
Python’s memory allocation
and deallocation method is
automatic.
Direct support for
exception handling is not
supported by C.
Exception handling is
supported by C++.
Exception handling is
supported by Python.
Different Types Of extension
Python scripts may have one of several file extensions. Each file extension has a special
meaning and purpose.
• *.py - Regular scripts
• *.py3 - (rarely used) Python3 script; Python3 scripts usually end with "*.py" not
"*.py3"
• *.pyc - compiled script (Bytecode)

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Python Notes
• *.pyo - optimized pyc bytecode file (As of Python3.5, Python will only use pyc
rather than pyo and pyc)
• *.pyw - Python script for Windows that is executed with pythonw.exe
• *.pyx - Cython src to be converted to C/C++
• *.pyd - Python script made as a Windows DLL
Q.Application of Phyton
1) Web Applications
We can use Python to develop web applications. It provides libraries to handle internet
protocols such as HTML and XML, JSON, Email processing, request, beautifulSoup,

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Python Notes
Feedparser, etc. One of Python web-framework named Django is used on Instagram. Python
provides many useful frameworks, and these are given below:
o Django and Pyramid framework(Use for heavy applications)
o Flask and Bottle (Micro-framework)
o Plone and Django CMS (Advance Content management)
2) Desktop GUI Applications
The GUI stands for the Graphical User Interface, which provides a smooth interaction to any
application. Python provides a Tk GUI library to develop a user interface. Some popular GUI
libraries are given below.
o Tkinter or Tk
o wxWidgetM
o Kivy (used for writing multitouch applications )
o PyQt or Pyside
3) Console-based Application
Console-based applications run from the command-line or shell. These applications are
computer program which are used commands to execute. This kind of application was more
popular in the old generation of computers. Python can develop this kind of application very
effectively. It is famous for having REPL, which means the Read-Eval-Print Loop that makes
it the most suitable language for the command-line applications.
Python provides many free library or module which helps to build the command-line apps. The
necessary IO libraries are used to read and write. It helps to parse argument and create console
help text out-of-the-box. There are also advance libraries that can develop independent console
apps.
4) Software Development
Python is useful for the software development process. It works as a support language and can
be used to build control and management, testing, etc.
o SCons is used to build control.

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Python Notes
o Buildbot and Apache Gumps are used for automated continuous compilation and
testing.
o Round or Trac for bug tracking and project management.
5) Scientific and Numeric
This is the era of Artificial intelligence where the machine can perform the task the same as
the human. Python language is the most suitable language for Artificial intelligence or machine
learning. It consists of many scientific and mathematical libraries, which makes easy to solve
complex calculations.
Implementing machine learning algorithms require complex mathematical calculation. Python
has many libraries for scientific and numeric such as Numpy, Pandas, Scipy, Scikit-learn, etc.
If you have some basic knowledge of Python, you need to import libraries on the top of the
code. Few popular frameworks of machine libraries are given below.
o SciPy
o Scikit-learn
o NumPy
o Pandas
o Matplotlib
6) Business Applications
Business Applications differ from standard applications. E-commerce and ERP are an example
of a business application. This kind of application requires extensively, scalability and
readability, and Python provides all these features.
Oddo is an example of the all-in-one Python-based application which offers a range of business
applications. Python provides a Tryton platform which is used to develop the business
application.
7) Audio or Video-based Applications
Python is flexible to perform multiple tasks and can be used to create multimedia applications.
Some multimedia applications which are made by using Python are TimPlayer, cplay, etc.
The few multimedia libraries are given below.
o Gstreamer

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Python Notes
o Pyglet
o QT Phonon
8) 3D CAD Applications
The CAD (Computer-aided design) is used to design engineering related architecture. It is used
to develop the 3D representation of a part of a system. Python can create a 3D CAD application
by using the following functionalities.
o Fandango (Popular )
o CAMVOX
o HeeksCNC
o AnyCAD
o RCAM
9) Enterprise Applications
Python can be used to create applications that can be used within an Enterprise or an
Organization. Some real-time applications are OpenERP, Tryton, Picalo, etc.
10) Image Processing Application
Python contains many libraries that are used to work with the image. The image can be
manipulated according to our requirements. Some libraries of image processing are given
below.
• OpenCV
• Pillow
• SimpleITK
Disadvantages of Python
1. Slow Speed
Python is an interpreted language and dynamically-typed language.
The line by line execution of code often leads to slow execution.
2. Not Memory Efficient

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Python Notes
To provide simplicity to the developer, Python has to do a little tradeoff.
The Python programming language uses a large amount of memory.
This can be a disadvantage while building applications when we prefer memory optimization.
3. Weak in Mobile Computing
Python is generally used in server-side programming.
It don’t get to see Python on the client-side or mobile applications because of the following
reasons.
Python is not memory efficient and it has slow processing power as compared to other
languages.
4. Database Access
Programming in Python is easy and stress-free.
But when it are interacting with the database, it lacks behind.
The Python’s database access layer is primitive and underdeveloped in comparison to the
popular technologies like JDBC and ODBC.
Huge enterprises need smooth interaction of complex legacy data and Python is thus rarely
used in enterprises.
5. Runtime Errors
Python is a dynamically typed language so the data type of a variable can change anytime.
A variable containing integer number may hold a string in the future, which can lead
to Runtime Errors.
Therefore Python programmers need to perform thorough testing of the applications.
Q. First Program In Python
1.
>>> print("Hello, World!")
o/p Hello, World!

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Python Notes
OR
Save above file p.py
Run =>python p.py
Q. Python Identifiers
An identifier is a name given to entities like class, functions, variables, etc. It helps to
differentiate one entity from another.
Rules for writing identifiers
1. Identifiers can be a combination of letters in lowercase (a to z) or uppercase (A to Z) or
digits (0 to 9) or an underscore _. Names like myClass, var_1 and print_this_to_screen, all are
valid example.
2. An identifier cannot start with a digit.
3. Keywords cannot be used as identifiers.
4. An identifier can be of any length.
5. Python is a case-sensitive language. This means, Variable and variable are not the same.
Valid Identifier
Salay, sum_sal etc
Q.Python Keywords
• Keywords are the reserved words in Python.

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Python Notes
• It cannot use a keyword as a variable name, function name or any other identifier. They
are used to define the syntax and structure of the Python language.
• In Python, keywords are case sensitive.
• There are 33 keywords in Python 3.7. This number can vary slightly over the course of
time.
• All the keywords except True, False and None are in lowercase and they must be
written as they are. The list of all the keywords is given below.
False await else import pass
None break except in raise
True class finally is return
And continue For lambda try
As def from nonlocal while
Assert del global not with
Async elif if or yield

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Python Notes
Q.Python Comments
1. Single Line Comment
It is used to single line comment by using #
e.g
#print("Hello,World!")
2. Multi line comment
It is used to “”” (tripal quotes)
e.g
"""
This is python
This is Java
"""
Q.Lines and Indentation
Python provides no braces to indicate blocks of code for class and function definitions or flow
control. Blocks of code are denoted by line indentation.
Indentation refers to the spaces at the beginning of a code line.
Python uses indentation to indicate a block of code.
The number of spaces in the indentation is variable, but all statements within the block must
be indented the same amount
Note:
1.Semicolon at the end of statement is optional
2.Instead of {},indentations are used to represent block

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Python Notes
For e.g 1:valid
if condtion:
statement
statement
For e.g 2 : invalid
if condtion:
statement
statement
else:
statement
statement
Multi-Line Statements
Explicit Line Continuation
• Statements in Python typically end with a new line. Python does, however, allow the
use of the line continuation character () to denote that the line should continue. For
example −
total = item_one +
item_two +
item_three
Implicit Line continuation
• Statements contained within the [], {}, or () brackets do not need to use the line
continuation character. For example −
days = ['Monday', 'Tuesday', 'Wednesday',
'Thursday', 'Friday']
Q.Variables
Python has no command for declaring a variable.
A variable is created the moment you first assign a value to it.
x=5

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Python Notes
y=”vision”
print(x)
print(y)
type()
Get the data type of a variable with the type() function.
x= 5
y= "John"
print(type(x))o/p===➔<class=’int’>
print(type(y)) /p===➔<class 'str'>
Q.Data Type
Python supports three types of numeric data.
1. Int - Integer value can be any length such as integers 10, 2, 29, -20, -150 etc. Python
has no restriction on the length of an integer. Its value belongs to int
e.g. x = 20

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Python Notes
2. Float - Float is used to store floating-point numbers like 1.9, 9.902, 15.2, etc. It is
accurate upto 15 decimal points.
e.g. x = 20.5
3. complex - A complex number contains an ordered pair, i.e., x + iy where x and y denote
the real and imaginary parts, respectively. The complex numbers like 2.14j, 2.0 + 2.3j,
etc.
e.g x = 1j
Q.Python Operators
Operators are used to perform operations on variables and values.
Python divides the operators in the following groups:
• Arithmetic operators
• Assignment operators
• Comparison operators
• Logical operators
• Identity operators
• Membership operators
• Bitwise operators
• Python Arithmetic Operators
Arithmetic operators
Operator
Name Example
+ Addition x + y

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Python Notes
- Subtraction x - y
* Multiplication x * y
/ Division x / y
% Modulus x % y
** Exponentiation x ** y
// Floor division x // y
Assignment Operators
Operator
Example Same As
= x = 5 x = 5
+= x += 3 x = x + 3
-= x -= 3 x = x - 3
*= x *= 3 x = x * 3
/= x /= 3 x = x / 3
%= x %= 3 x = x % 3
//= x //= 3 x = x // 3
**= x **= 3 x = x ** 3
&= x &= 3 x = x & 3
|= x |= 3 x = x | 3
^= x ^= 3 x = x ^ 3
>>= x >>= 3 x = x >> 3

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Python Notes
<<= x <<= 3 x = x << 3
Comparison Operators
Operator Name Example
== Equal x == y
!= Not equal x != y
> Greater than x > y
< Less than x < y
>= Greater than or equal to x >= y
<= Less than or equal to x <= y
Python Logical Operators
Operator Description Example
and Returns True if both statements are true x < 5 and x < 10
Or Returns True if one of the statements is true x < 5 or x < 4
Not Reverse the result, returns False if the result is true not(x < 5 and x < 10)
Python Identity Operators
• Identity operators are used to compare the objects, not if they are equal, but if they are
actually the same object, with the same memory location:

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Python Membership Operators
Membership operators are used to test if a sequence is presented in an object:
Operator Description
Example
in Returns True if a sequence with the specified value
is present in the object
x in y
not in Returns True if a sequence with the specified value
is not present in the object
x not in y
Python Bitwise Operators
Bitwise operators are used to compare (binary) numbers:
Operator Name
& AND
| OR
^ XOR
Operator Description
Example
is Returns true if both variables are the same object x is y
is not Returns true if both variables are not the same object x is not y

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Python Notes
~ NOT
<< Zero fill left shift
>> Signed right shift
Data Type Conversion
Sr.No. Function & Description
1 int(x[,base])
Converts x to an integer. base specifies the base if x is a string.
2 long(x[,base])
Converts x to a long integer. base specifies the base if x is a string.
3 float(x)
Converts x to a floating-point number.
4 complex(real[,imag])
Creates a complex number.
5 str(x)
Converts object x to a string representation.
6 repr(x)
Converts object x to an expression string.

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7 eval(str)
Evaluates a string and returns an object.
8 tuple(s)
Converts s to a tuple.
9 list(s)
Converts s to a list.
10 set(s)
Converts s to a set.
11 dict(d)
Creates a dictionary. d must be a sequence of (key,value) tuples.
12 frozenset(s)
Converts s to a frozen set.
13 chr(x)
Converts an integer to a character.
14 unichr(x)
Converts an integer to a Unicode character.
15 ord(x)
Converts a single character to its integer value.
16 hex(x)
Converts an integer to a hexadecimal string.

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17 oct(x)
Converts an integer to an octal string.
Q.print Function
The print() function prints the specified message to the screen, or other standard output device.
Syntax
print(object(s), sep=separator, end=end, file=file, flush=flush)
Parameter Values
Parameter Description
object(s) Any object, and as many as you like. Will be converted to string before printed
sep='separator' Optional. Specify how to separate the objects, if there is more than one. Default
is ' '
end='end' Optional. Specify what to print at the end. Default is 'n' (line feed)
File Optional. An object with a write method. Default is sys.stdout
Flush Optional. A Boolean, specifying if the output is flushed (True) or buffered
(False). Default is False

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Python Notes
e.g
1.print("Hello", "how are you?")
2.c=4
print('value is', c) o/p==➔value is c
3.b = "for"
print("Geeks", b , "Geeks") o/p===➔Greeks for Greeks
4.print(1,2,3,4) o/p=➔1 2 3 4
5.print(1,2,3,4,sep=’#’,end=’&’) o/p➔1#2#3#4&
6.print(1,2,3,4,sep=’*’) o/p➔1*2*3*4
Q.input function
The input() function allows user input.
Syntax
input(prompt)
Where
prompt=>A string, representing default message before input

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Python Notes
e.g
x = input('”enter value'”)
print('”Hello”,x)
Addition of two nos
a = input('enter value1')
b=input('enter value2')
c=int(a)+int(b)
print('addition is',c)
Q.Control Statement
1.condtional statement
1.if statement
Syntax
if boolean-expression:
#statements
e.g
a= 33
b= 200
if b>a:
print("b is greater than a")
2.if-else statement
Syntax

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Python Notes
#statements
else:
#statements
e.g
i = 10
if i % 2 == 0:
print("Number is even")
else:
print("Number is odd")
3. Nested if-elif
Syntax
#statements
elif boolean-expression:
#statements
#statements
#statements
else:
#statements
e.g
1.
a= 200
b= 33
if b>a:
print(“bismax”)
elif a==b:
print("aandbareequal")
else:
print("a is greater than b")

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Python Notes
e.g
2
x= 41
if x> 10:
print("Aboveten,")
if x> 20:
print("andalsoabove20!")
else:
print("but not above 20.")
Loop
1. While
Syntax
while expression:
statement(s)
e.g
count = 0
while (count < 9):
print 'The count is:', count
count = count + 1
2.For loop
Syntax
for iterating_var in sequence:
statements(s)
e.g
for ch in 'vision':
print 'Current Letter :', ch

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The range() function returns a sequence of numbers, starting from 0 by default, and increments
by 1 (by default), and stops before a specified number.
Syntax
range(start, stop, step)
Parameter Description
Start Optional. An integer number specifying at which position to start.
Default is 0
Stop Required. An integer number specifying at which position to stop
(not included).
Step Optional. An integer number specifying the incrementation. Default
is 1
x= range(3, 6)
for n in x:
print(n)
o/p 3 4 5

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x= range(3, 10, 2)
for n in x:
print(n)
o/p 3 5 7 9
Using Else Statement in loop
for x in range(6):
print(x)
else:
print("Fi+inally finished!")
o/p 0 1 2 3 4 5
finallyfinished
Break & Continue Statement
1.
i= 1
while i< 6:
print(i)
if i== 3:

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Python Notes
break
i = i+1
2.
i= 0
while i< 6:
i+= 1
if i== 3:
continue
print(i)
Pass statement
pass is a null statement. The interpreter does not ignore a pass statement, but nothing happens
and the statement results into no operation.
The pass statement is generally used as a placeholder
i.e. when the user does not know what code to write. So user simply places pass at that line.
Sometimes, pass is used when the user doesn’t want any code to execute. So user simply
places pass there as empty code. Empty code is not allowed in loops, function definitions,
class definitions, or in if statements. So using pass statement user avoids this error.
e.g
1.
a = 33
b = 200
if b > a:
pass
print("pass statement")
2.

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Python Notes
def myfunction():
pass
Note: The pass statement is a null statement. But the difference between pass and comment
is that comment is ignored by the interpreter whereas pass is not ignored.
Q.Math Function
List of Functions in Python Math Module
Function Description
ceil(x) Returns the smallest integer greater than or equal to x.
copysign(x, y) Returns x with the sign of y
fabs(x) Returns the absolute value of x
factorial(x) Returns the factorial of x
floor(x) Returns the largest integer less than or equal to x
fmod(x, y) Returns the remainder when x is divided by y
frexp(x)
Returns the mantissa and exponent of x as the pair (m,
e)
fsum(iterable)
Returns an accurate floating point sum of values in the
iterable
isfinite(x)
Returns True if x is neither an infinity nor a NaN (Not a
Number)
isinf(x) Returns True if x is a positive or negative infinity

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isnan(x) Returns True if x is a NaN
ldexp(x, i) Returns x * (2**i)
modf(x) Returns the fractional and integer parts of x
trunc(x) Returns the truncated integer value of x
exp(x) Returns e**x
expm1(x) Returns e**x - 1
log(x[, b]) Returns the logarithm of x to the base b (defaults to e)
log1p(x) Returns the natural logarithm of 1+x
log2(x) Returns the base-2 logarithm of x
log10(x) Returns the base-10 logarithm of x
pow(x, y) Returns x raised to the power y
sqrt(x) Returns the square root of x
acos(x) Returns the arc cosine of x
asin(x) Returns the arc sine of x
atan(x) Returns the arc tangent of x
atan2(y, x) Returns atan(y / x)
cos(x) Returns the cosine of x
hypot(x, y) Returns the Euclidean norm, sqrt(x*x + y*y)

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sin(x) Returns the sine of x
tan(x) Returns the tangent of x
degrees(x) Converts angle x from radians to degrees
radians(x) Converts angle x from degrees to radians
acosh(x) Returns the inverse hyperbolic cosine of x
asinh(x) Returns the inverse hyperbolic sine of x
atanh(x) Returns the inverse hyperbolic tangent of x
cosh(x) Returns the hyperbolic cosine of x
sinh(x) Returns the hyperbolic cosine of x
tanh(x) Returns the hyperbolic tangent of x
erf(x) Returns the error function at x
erfc(x) Returns the complementary error function at x
gamma(x) Returns the Gamma function at x
lgamma(x)
Returns the natural logarithm of the absolute value of the
Gamma function at x
Pi
Mathematical constant, the ratio of circumference of a
circle to it's diameter (3.14159...)
E mathematical constant e (2.71828...)
import math

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print(math.pi)
Q.String
String is sequence of character.
String declaration
1.Using Double quotes
a=”Hello”
print(a)
2.UsingSingleQuotes
a=’hello’
print(a)
2.Multiline Strings
You can assign a multiline string to a variable by using three quotes:
1.Using 3 double quotes
a= """visionacademy,
classesforbcs/bca/bba."""
print(a)
2.Using 3 Single quotes
a= '''visionacademy,classesforbcs/bca/bba.'''
print(a)
Representations of String

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• Strings are stored individual character in contiguous location
• It can access from both direction (forward & backward)
• Both forward & backword indexing are provided using string in python
Forward indexing start with 0,1,2,3,…
Backward indexing start with -1,-2,-3……..
Escape Characters
Code Result
' Single Quote
Backslash
n New Line
r Carriage Return
t Tab
b Backspace
f Form Feed
ooo Octal value
xhh Hex value

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Python Notes
e.g
txt = "HellonWorld!"
print(txt)
Slicing a String
If S is a string, the expression S [ start : stop : step ] returns the portion of the string from
index start to index stop, at a step size step.
Syntax
Basic Example
Here is a basic example of string slicing.
S = ' A B C D E F G H I '
print(S[2:7]) # C D E F G

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Python Notes
Note that the item at index 7 'H' is not included.
Slice with Negative Indices
You can also specify negative indices while slicing a string.
print(S[-7:-2]) # C D E F G
Slice with Positive & Negative Indices
You can specify both positive and negative indices at the same time.

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print(S[2:-5]) # C D
Specify Step of the Slicing
You can specify the step of the slicing using step parameter. The step parameter is optional
and by default 1.
# Return every 2nd item between position 2 to 7
print(S[2:7:2]) # C E G
Negative Step Size
You can even specify a negative step size.
# Returns every 2nd item between position 6 to 1 in reverse order
print(S[6:1:-2]) # G E C
Slice at Beginning & End
Omitting the start index starts the slice from the index 0. Meaning, S[:stop] is equivalent
to S[0:stop]
# Slice first three characters from the string
print(S[:3]) # A B C

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Whereas, omitting the stop index extends the slice to the end of the string.
Meaning, S[start:] is equivalent to S[start:len(S)]
# Slice last three characters from the string
print(S[6:]) # G H I
String operator
String Special Operators
Assume string variable a holds 'Hello' and variable b holds 'Python', then −
+ Concatenation - Adds values on either side of the operator a + b will give
HelloPython
* Repetition - Creates new strings, concatenating multiple
copies of the same string
a*2 will give -
HelloHello
[] Slice - Gives the character from the given index a[1] will give e
[ : ] Range Slice - Gives the characters from the given range a[1:4] will give ell
b[2:]=>thon
b[:3]=>Pyt
b[-4:-2]=>th

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Python Notes
In Membership - Returns true if a character exists in the given
string
H in a =>1
not in Membership - Returns true if a character does not exist in
the given string
M not in a =>1
% Format - Performs String formatting
Build-in String Method
Method Description
capitalize() Converts the first character to upper case
e.g
txt= "hello,andwelcometomyworld."
x=txt.capitalize()
print (x)
casefold() Converts string into lower case
center() Returns a centered string
count() Returns the number of times a specified value occurs in a string
txt= "Iloveapples,applearemyfavoritefruit"
x=txt.count("apple")
print(x)
encode() Returns an encoded version of the string
endswith() Returns true if the string ends with the specified value
expandtabs() Sets the tab size of the string

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Python Notes
find() Searches the string for a specified value and returns the position of
where it was found
txt= "Hello,welcometomyworld."
x=txt.find("welcome")
print(x)
format() Formats specified values in a string
format_map() Formats specified values in a string
index() Searches the string for a specified value and returns the position of
where it was found
isalnum() Returns True if all characters in the string are alphanumeric
isalpha() Returns True if all characters in the string are in the alphabet
isdecimal() Returns True if all characters in the string are decimals
isdigit() Returns True if all characters in the string are digits
txt= "50800"
x=txt.isdigit()
print(x)
isidentifier() Returns True if the string is an identifier
islower() Returns True if all characters in the string are lower case
isnumeric() Returns True if all characters in the string are numeric
isprintable() Returns True if all characters in the string are printable
isspace() Returns True if all characters in the string are whitespaces
istitle() Returns True if the string follows the rules of a title
isupper() Returns True if all characters in the string are upper case
join() Joins the elements of an iterable to the end of the string
ljust() Returns a left justified version of the string
lower() Converts a string into lower case

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txt= "HellomyFRIENDS"
x=txt.lower()
print(x)
lstrip() Returns a left trim version of the string
maketrans() Returns a translation table to be used in translations
partition() Returns a tuple where the string is parted into three parts
replace() Returns a string where a specified value is replaced with a specified
value
txt= "Ilikebananas"
x=txt.replace("bananas", "apples")
print(x)
rfind() Searches the string for a specified value and returns the last position
of where it was found
rindex() Searches the string for a specified value and returns the last position
of where it was found
rjust() Returns a right justified version of the string
rpartition() Returns a tuple where the string is parted into three parts
rsplit() Splits the string at the specified separator, and returns a list
rstrip() Returns a right trim version of the string
split() Splits the string at the specified separator, and returns a list
txt= "welcometothejungle"
x=txt.split()
print(x)
splitlines() Splits the string at line breaks and returns a list
startswith() Returns true if the string starts with the specified value
strip() Returns a trimmed version of the string
swapcase() Swaps cases, lower case becomes upper case and vice versa
title() Converts the first character of each word to upper case

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Python Notes
translate() Returns a translated string
upper() Converts a string into upper case
txt= "Hellomyfriends"
x=txt.upper()
print(x)
zfill() Fills the string with a specified number of 0 values at the beginning
Q List
• A list in Python is used to store the sequence of various types of data.
• Python lists are mutable(Its mean it can modify its element after it created).
• A list can be defined as a collection of values or items of different types. The items in
the list are separated with the comma (,) and enclosed with the square brackets [].
• It allowed duplicate value
Syntax
Listname=[value1, value2,…..valuen]
e.g
list1 = ["apple", "banana", "cherry", "apple", "cherry"]
list2 = ["abc", 34, True, 40, "male"]
print(list1)
print(list2)
o/p
["apple", "banana", "cherry", "apple", "cherry"]
[‘abc’, 34, True, 40, ‘male’]

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Python Notes
Display List using loop
list=["apple", "banana", "cherry"]
for i in range(len(list)):
print(list[i])
OR
list = ["apple", "banana", "cherry"]
for x in list:
print(x)
Accessing Element in List
List index
e.g
list1=["apple", "banana", "cherry"]
print(list1[1] o/p=>bannan
print(list1[-1]) o/p=>cherry
Slicing List
e.g
list1=["apple", "banana", "cherry", "orange", "kiwi", "melon", "mango"]
print(list1[2:5]) o/p=>[‘cherry’,’orange’,’kiwi’]
print(thislist[:4]) o/p=>[‘apple’,’banana’,’cherry’,’orange’]
print(thislist[2:]) o/p=>[‘cherry’,’kiwi’,’melon’,’msngo’]
print(thislist[-4:-1]) o/p=>[‘orange’,’kiwi’,’melon’]
Inserting Item

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Python Notes
thislist=["apple", "banana", "cherry"]
thislist.insert(2, "watermelon")
print(thislist) o/p=➔[‘apple’, ‘banana’,’watermelon’, "cherry"]
Updating List
list = ['physics', 'chemistry', 1997, 2000];
print "Value available at index 2 : "
print list[2] o/p=➔1997
list[2] = 2001;
print "New value available at index 2 : "
print list[2] o/p➔2001
Change a Range of Item Values
thislist=["apple", "banana", "cherry", "orange", "kiwi", "mango"]
thislist[1:3]=["blackcurrant", "watermelon"]
print(thislist)
o/p[‘apple’,’blackcurrant’,watermelon’,’orange’,’kiwi’,’mango’]
thislist[1:2]=["blackcurrant", "watermelon"]
print(thislist)
o/p[‘apple’,’balckcurrent’,’watermelon’]
thislist[1:3]=["watermelon"]
print(thislist)

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Python Notes
o/p [‘apple’,’watermelon’]
Remove Item
1.remove():The remove() method removes the specified item.
list.remove("banana")
print(list)
o/p [‘apple’,’cherry’]
2.pop():The pop() method removes the specified index.
list.pop(1)
print(list)
o/p [‘apple’,’cherry’]
If you do not specify the index, the pop() method removes the last item.
list.pop()
print(list)
o/p [‘apple’,’banana’]
3.Del():The del keyword also removes the specified index
del list[0]
print(list)

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Python Notes
o/p [‘banana’,’cherry’]
The del keyword can also delete the list completely.
del list
4.clear():The clear() method empties the list
list = ["apple", "banana", "cherry"]
list.clear()
print(thislist)
Method Description
append() Adds an element at the end of the list fruits = ['apple', 'banana', 'cherry']
fruits.append("orange")
print(x)
copy() Returns a copy of the list fruits = ["apple", "banana", "cherry"]
x = fruits.copy()
print(x)
count() Returns the number of elements with
the specified value
fruits = ["apple", "banana", "cherry"]
x = fruits.count("cherry")
print(x)
extend() Add the elements of a list (or any
iterable), to the end of the current list
fruits = ['apple', 'banana', 'cherry']
cars = ['Ford', 'BMW', 'Volvo']
fruits.extend(cars)
print(fruits)
index() Returns the index of the first element
with the specified value
fruits = ['apple', 'banana', 'cherry']
x = fruits.index("cherry")
print(x)

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o/p 2
reverse() Reverses the order of the list fruits = ['apple', 'banana', 'cherry']
fruits.reverse()
print(fruits)
sort() Sorts the list cars = ['Ford', 'BMW', 'Volvo']
cars.sort()
print(cars)
List Comprehension
It is a one line for loop that produce python list data structure. It is complete substitute for
labda function as well as function map(),filter() & reduce function.
Syntax
newlist = [expression for item in iterable if condition == True]
e.g 1
Where
The expression is the current item in the iteration
fruits=["apple", "banana", "cherry", "kiwi", "mango"]
newlist=[x for x in fruits if "a" in x]
print(newlist)
o/p["apple", "banana", "mango"]
e.g 2
newlist = [x for x in range(10)]
print(newlist)

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Python Notes
o/p
[0,1,2,3,4,5,6,7,8,9]
Q Python Tuple
1. Tuples are used to store multiple items in a single variable.
2. Tuples are written with round brackets.
3. A tuple is a is ordered collection & immutable(The value of the items stored in
the tuple cannot be changed after tuple has been created)
4. It allowed duplicate
Syntax
tupleame=(value1, value2,…..valuen)
e.g
tuple=("apple", "banana", "cherry")
print(tuple)
o/p
(‘apple’, ‘banana’, ‘cherry’)
Display tuple using loop
t=("apple", "banana", "cherry")
for i in range(len(t)):
print(t[i])
Or
t = ("apple", "banana", "cherry")
for x in t:
print(x)
Accessing Element in Tuple

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Python Notes
Tuple index
e.g
tuple=("apple", "banana", "cherry")
print(tuple[1]) o/p=>bannan
print(tuple[-1]) o/p=>cherry
Slicing
e.g
t = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango")
print(t[2:5]) ➔ o/p (‘cherry’, ‘orange’, ‘kiwi’)
print(t[:4]) o/p=>(‘apple’,’banana’,’cherry’,’orange’)
print(t[2:]) o/p=>(‘cherry’,’kiwi’,’melon’,’mango’)
print(t[-4:-1]) o/p=>(‘orange’,’kiwi’,’melon’)
Update Tuple
Once a tuple is created, you cannot change its values. Tuples are unchangeable,
or immutable as it also is called.
It can convert the tuple into a list, change the list, and convert the list back into a tuple
Add Items
thistuple=("apple", "banana", "cherry")
y= list(thistuple)
y.append("orange")
thistuple= tuple(y)
o/p (‘apple’, ‘banana’, ‘cherry’, ’orange’)

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Update Items
x=("apple", "banana", "cherry")
y= list(x)
y[1]= "kiwi"
x= tuple(y)
print(x)
o/p(‘apple’, ‘kiwi’, ‘cherry’)
Remove Item
thistuple=("apple", "banana", "cherry")
y= list(thistuple)
y.remove("apple")
thistuple = tuple(y)
print(thistuple)
o/p(‘banana’, ‘cherry’)
Packing Tuple
When we create a tuple, It normally assign values to it. This is called "packing" a tuple
fruits = ("apple", "banana", "cherry")
print(fruits)
Unpacking Tuple
It allowed to extract the values back into variables. This is called "unpacking"
fruits=("apple", "banana", "cherry")
(green,yellow,red)=fruits
print(green) o/p=>apple

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Python Notes
print(yellow) o/p=>banana
print(red) o/p=>cherry
Basic Tuple operations
The operators like concatenation (+), repetition (*), Membership (in) works in the same way
as they work with the list. Consider the following table for more detail.
Let's say Tuple T1 = (1, 2, 3, 4, 5) and Tuple T2 = (6, 7, 8, 9) are declared.
Repetition The repetition operator enables the tuple
elements to be repeated multiple times.
T2=T1*2
(1, 2, 3, 4, 5, 1,
2, 3, 4, 5)
Concatenation It concatenates the tuple mentioned on
either side of the operator.
T3=T1+T2
o/p
(1, 2, 3, 4, 5, 6, 7,
8, 9)
Membership It returns true if a particular item exists
in the tuple otherwise false
print (2 in T1)
prints True.

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Python Notes
Iteration The for loop is used to iterate over the
tuple elements.
for i in T1:
print(i)
Output
1
2
3
4
5
Length It is used to get the length of the tuple. len(T1) = 5
Build In function
Sr.No. Function with Description Eg
1 cmp(tuple1, tuple2)
Compares elements of both tuples.
It return following result
list1 = [ 1, 2, 4, 3]
list2 = [ 1, 2, 5, 8]
list3 = [ 1, 2, 5, 8, 10]
list4 = [ 1, 2, 4, 3]

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If T1>T2 return(1)
If T1=T2 return(0)
If T1<T2 return(-1)
print cmp(list2, list1) o/p 1
print cmp(list2, list3) o/p -1
print cmp(list4, list1) o/p 0
2 len(tuple)
Gives the total length of the tuple.
t(1,2,3)
print len(t) o/p 3
3 max(tuple)
Returns item from the tuple with max
value.
t(1,2,3)
print max(t) o/p 3
4 min(tuple)
Returns item from the tuple with min
value.
t(1,2,3)
print min(t) o/p 1
5 tuple(seq)
Converts a list into tuple.
aList = [123, 'xyz', 'zara', 'abc']
aTuple = tuple(aList)
print aTuple
o/p
(123,’xyz’,’zara’)

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Python Notes
Sr.no List Tuple
1 The literal syntax of list is
shown by the [].
The literal syntax of the tuple is
shown by the ().
2 The List is mutable. The tuple is immutable.
3 The List has the a variable
length.
The tuple has the fixed length.
4 The list provides more
functionality than a tuple.
The tuple provides less
functionality than the list.
5 List iteration is slower and is
time consuming
Tuple iteration is faster
6 The lists are more memory The tuples are less memory.
7. L=[1,2,3] T=(1,2,3)

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Python Notes
Q.Set
• Sets are used to store multiple items in a single variable.
• A set is a collection which is both unordered and unindexed.
• Sets are written with curly brackets { }.
• It doesn’t allowed duplicate value
• It is immutable(The value of the items stored in the set cannot be changed after set has
been created)
Syntax
tupleame={value1, value2,…..valuen}
thisset = {"apple", "banana", "cherry"}
print(thisset)
o/p {‘apple’, ‘cherry’, ’banana’}
Display Set using loop
thisset={"apple", "banana", "cherry"}
for x in thisset:
print(x)
Update Set
1.Add Item
thisset.add("orange")
print(thisset)
2.To add items from another set into the current set, use the update() method.
tropical={"pineapple", "mango", "papaya"}

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Python Notes
thisset.update(tropical)
print(thisset)
3.To remove item using discard method
thisset.discard("banana")
print(thisset)
4 To remove all item using clear method
thisset.clear()
print(thisset)
Set Operation (Union, Intersection, Difference Symmetric )
A = {0, 2, 4, 6, 8};
B = {1, 2, 3, 4, 5};
# union
print("Union :", A | B)
# intersection
print("Intersection :", A & B)
# difference
print("Difference :", A - B)
# symmetric difference means it contain both sets but not in intersection
print("Symmetric difference :", A ^ B)
o/p
Union : {0, 1, 2, 3, 4, 5, 6, 8}
Intersection : {2, 4}
Difference : {0, 8, 6}
Symmetric difference : {0, 1, 3, 5, 6, 8}

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Python Notes
Q.Dictionaries
• Dictionaries are used to store data values in key:value pairs.
• A dictionary is a collection is unordered,
• It is changeable(mutable)
• It does not allow duplicates.
• Dictionaries are written with curly brackets{}, and have keys and values
Syntax
Dictionary name = {
<key>: <value>,
<key>: <value>,
.
.
.
<key>: <value>
}
e.g
thisdict ={
"brand": "Ford",
"model": "Mustang",
"year": 1964

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Python Notes
}
print(thisdict)
o/p
{ "brand": "Ford", "model": "Mustang", "year": 1964}
Loop Through a Dictionary
1. Print all key names in the dictionary, one by one
thisdict ={
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
for x in thisdict:
print(x)
2.Print all values in the dictionary, one by one
thisdict ={
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
for x in thisdict:

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Python Notes
print(thislist[x])
3.both keys and values, by using the items() method:
for x,y in thisdict.items():
print(x, y)
Access Value from Dictionary
thisdict ={
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
print ("thisdict[brand]:",thisdict["brand"]);
print ("thisdict[model]:",thisdict["model"]);
print ("thisdict[year]:",thisdict["year"]);
Update Dictionary
1.Add a Item
thisdict ={ "brand": "Ford",
"model": "Mustang",
"year": 1964
}
thisdict["color"] = "red"
print(thisdict)
2.Update Item

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Python Notes
The update() method will update the dictionary with the items from a given argument. If the
item does not exist, the item will be added.
The argument must be a dictionary, or an iterable object with key:value pairs.
thisdict =
{
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
thisdict.update({"color": "red"})
3.Remove Item
1.Using del method
thisdict= {
"brand": "Ford", "model": "Mustang",
"year": 1964
}
del thisdict["model"]
print(thisdict)
2.The del keyword can also delete the dictionary completely
thisdict= {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
del thisdict
print(thisdict)
2.The clear() method empties the dictionary

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Python Notes
thisdict= {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
thisdict.clear()
print(thisdict)
o/p {}
3. The pop() method removes the item with the specified key name
Thisdict {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
thisdict.pop("model")
print(thisdict)
4.The popitem() method removes the last inserted item
thisdict= {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
thisdict.popitem()
print(thisdict)
copy()

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Python Notes
Returns a copy of the dictionary
car = {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
x = car.copy()
print(x)
items()
Return the dictionary's key-value pairs
car={
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
x=car.items()
print(x)
get()
Returns the value of the specified key
car={
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
x=car.get("model")
print(x)
setdefault()

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Python Notes
Returns the value of the specified key. If the key does not exist: insert the key, with the specified
value
car = {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
x = car.setdefault("model", "Bronco")
print(x)
keys()
Returns a list containing the dictionary's keys
car={
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
x=car.keys()
print(x)
OR
for x in car.keys():
print(x)
values()
Returns a list of all the values in the dictionary
car={
"brand": "Ford",
"model": "Mustang",
"year": 1964
}

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Python Notes
x=car.values()
print(x)
OR
for x in thisdict.values():
print(x)
Q.Python Functions
• A function is a block of code which only runs when it is called.
• It can pass data, known as parameters, into a function.
• A function can return data as a result
Syntax
Python provides the def keyword to define the function
def functionname(parameters):
function_block
return expression
e.g 1
def display():
print("hello world")
display() # calling function
e.g 3
def sum(a,b):
c=a+b;

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Python Notes
return c;
a = 10
b = 20
print("The sum is:",sum(a,b)) # calling sum() function in print statement
Function Argument
There are 2 ways passing argument to the function
1.Call by Reference
It pass as address as parameter to the function
def change_list(list1):
list1.append(20)
list1.append(30)
print("list inside function = ",list1)
#defining the list
list1 = [10,30,40,50]
#calling the function
change_list(list1)
print("list outside function = ",list1)
o/p list inside function = [10, 30, 40, 50, 20, 30]
list outside function = [10, 30, 40, 50, 20, 30]
2. Call By value
It pass as value as parameter to the function
Types of arguments
There may be several types of arguments which can be passed at the time of function call.

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Python Notes
1. Required arguments
2. Keyword arguments
3. Default arguments
4. Variable-length arguments
1.Required arguments
• Required arguments are the argument passed to a function in correct positional order.
• No. of argument of the function call should match exactly with function definition
def calculate(a,b):
return a+b
calculate(10,20)
2.Default Arguments
Python allows us to initialize the arguments at the function definition. If the value of any of the
arguments is not provided at the time of function call, then that argument can be initialized
with the value given in the definition.
def printme(name,age=22):
print("My name is",name,"and age is",age)
printme("john")
3.Keyword arguments
• Python allows us to call the function with the keyword Arguments(key = value).
• This kind of function call will enable us to pass the arguments in the random order.
• The name of the arguments is treated as the keywords and matched in the function
calling and definition. If the same match is found, the values of the arguments are
copied in the function definition.

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Python Notes
def func(name,message):
print("printing the message with",name,"and ",message)
func(message="hello", name = "amit")
**kwargs
Python provides the facility to pass the multiple keyword arguments which can be
represented as **kwargs.
def food(**kwargs):
print(kwargs)
food(fruits="Orange", Vagitables="Carrot")
o/p
{'fruits': 'Orange', 'Vagitables': 'Carrot'}
Rules
• positional argument after keyword arguments will result in errors.
e.g
greet(name="amit","How do you do?")
• Non Default argument must present before default argument in function header
def greet(msg = "Good morning!", name): =➔error
4.Variable-length Arguments (*args)
The variable-length arguments can pass any number of arguments.
Syntax
*<variable - name >
def printme(*names):
print(names)
printme("john","David","smith","nick")

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Scope of variables
The variables are defined with the two types of scopes.
1. Global variables: variables declared inside the function known as Global Variable.
X=300;
def myfunc():
global x;#if not declared global keyword then it consider local
x= 200;
print(x);
myfunc()
print(x)
2. Local variables: variables declared outside the function known as Global Variable.
def myfunc():
x= 300
print(x)
myfunc()
Recursion
It is mechanism to calling itself known as recursion.
def factorial(n):
if n == 1:
return n
else:
return n * factorial(n-1)
n=3;
f=factorial(n);
print(f);

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Anonymous Function
• A function without name known as anonymous function.
• In Python anonymous function define by using Lambda function
• A lambda function can take any number of arguments, but can only have one
expression.
Syntax
lambda arguments : expression
e.g 1
x= lambda a:a+ 10
print(x(5))
e.g 2
x= lambda a,b,c:a+b+c
print(x(5, 6, 2))
e.g 3 Use as an anonymous function inside another function
def myfunc(n):
return lambda a:a*n
mydoubler=myfunc(2)
print(mydoubler(11))
Function Programming Tools

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Python Notes
(filter(),map(),reduce())
Map()
The map() function in Python takes in a function and a list as an argument. The function is
called with a lambda function and a list and a new list is returned which contains all the
lambda modified items returned by that function for each item
Syntax
Map(finction,list)
li = [5, 7, 22, 97, 54, 62, 77, 23, 73, 61]
final_list = list(map(lambda x: x*2, li))
print(final_list)
o/p
[10, 14, 44, 194, 108, 124, 154, 46, 146, 122]
Filter()
The filter() function in Python takes in a function and a list as arguments. This offers an
elegant way to filter out all the elements of a sequence “sequence”, for which the function
returns True.
Syntax
Filter(function,list)
li = [5, 7, 22, 97, 54, 62, 77, 23, 73, 61]
final_list = list(filter(lambda x: (x%2 != 0) , li))
print(final_list)
o/p
[5, 7, 97, 77, 23, 73, 61]

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Python Notes
Reduce()
The reduce() function in Python takes in a function and a list as an argument. The function
is called with a lambda function and an iterable and a new reduced result is returned. This
performs a repetitive operation over the pairs of the iterable. The reduce() function belongs
to the functools module.
Syntax
reduce(function, sequence[, initial])
from functools import reduce
li = [5, 8, 10, 20, 50, 100]
sum = reduce((lambda x, y: x + y), li)
print (sum)
o/p 193
Q.Packing and Unpacking Arguments
1.args*
• It can use * to unpack the list so that all elements of it can be passed as different
parameters
• The single asterisk(*) form of *args can be used as parameter to send non keyworded
Variable-length argument list to a functions.
• * used for tuple
def fun(a, b, c, d):
print(a, b, c, d)
# Driver Code
my_list = [1, 2, 3, 4]
# Unpacking list into four arguments
fun(*my_list)

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o/p
(1,2,3,4)
2.**kwargs
• It is used to pass a keyworded, variable length argument dictionary to a function.
• ** is used for dictionaries.
def fun(a, b, c):
print(a, b, c)
# A call with unpacking of dictionary
d = {'a':2, 'b':4, 'c':10}
fun(**d)
o/p
2 4 10
Function Object(First Class Function)
First class objects in a language are handled uniformly throughout. They may be stored in
data structures, passed as arguments, or used in control structures. A programming language
is said to support first-class functions if it treats functions as first-class objects. Python
supports the concept of First Class functions
Properties
• A function is an instance of the Object type.
• You can store the function in a variable.
• You can pass the function as a parameter to another function.
• You can return the function from a function.
• You can store them in data structures such as hash tables, lists, …
Python functions are first class objects. In the example below, we are assigning function to a
variable. This assignment doesn’t call the function. It takes the function object referenced by
shout and creates a second name pointing to it, yell
# Python program to illustrate functions
# can be treated as objects

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def shout(text):
return text.upper()
print (shout('Hello'))
yell = shout
print (yell('Hello'))
Function Duck Type
Duck Typing is a type system used in dynamic languages. Python doesn’t care about which
class of object it is, if it is an object & required behaviours is present for that object then it
will work. The type of object is distinguished only at runtime. This is called as duck typing.
The name Duck Typing comes from the phrase:
“If it looks like a duck and quacks like a duck, it’s a duck”
class Bird:
def fly(self):
print("fly with wings")
class Airplane:
def fly(self):
print("fly with fuel")
class Fish:
def swim(self):
print("fish swim in sea")
for obj in Bird(), Airplane(), Fish():
obj.fly()
o/p
fly with wings
fly with fuel
AttributeError: 'Fish' object has no attribute 'fly

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Generator
Python generator gives us easier way to create python iterators. A generator is a function that
return an object(iterator) which it can iterate over(one value at a time)
Generators Function
• Defined with the def keyword
• Use the yield keyword
• May contain several yield keywords.
• Returns an iterator.
Generator Object
Generator Function return a generator object. It is used either by calling the next method
on generator object or using the generator object in for in loop
e.g
def gen():
yield 1
yield 2
yield 3
for i in gen():
print(i)
o/p
1
2
3
def gen():
yield 1
yield 2
yield 3
x=gen()
print(x.__next__())
print(x.__next__())
print(x.__next__())
o/p
1
2
3

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Python Notes
It is as easy as defining a normal function, but with a yield statement instead of
a return statement.
The difference is that while a return statement terminates a function entirely, yield statement
pauses the function saving all its states and later continues from there on successive calls.
Differences between Generator function and Normal function
• Generator function contains one or more yield statements.
• When called, it returns an object (iterator) but does not start execution immediately.
• Methods like __iter__() and __next__() are implemented automatically. So we can
iterate through the items using next().
• Once the function yields, the function is paused and the control is transferred to the
caller.
• Local variables and their states are remembered between successive calls.
Factorial no
def gen(n):
f=1
i=1
while i<=n:
f=f*i
i=i+1
yield f
n=int(input("enter val"))
for i in gen(n):
print(i)
Generator Expression
Python also provides a generator expression, which is a shorter way of defining simple
generator functions. The generator expression is an anonymous generator function.

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Python Notes
A generator expression looks similar to a list comprehension but the simple difference is
that it uses parenthesis over square brackets.
list comprehension produces the entire list, generator expression produces one item at a
time
Syntax
genexpr=(expression for item in collection)
sq = (x*x for x in range(5))
for i in sq:
print(i)
Python Iterators
• An iterator is an object that contains a countable number of values.
• An iterator is an object that can be iterated upon, meaning that you can traverse through
all the values.
• Python, an iterator is an object which implements the iterator protocol, which consist
of the methods __iter__() and __next__().
Lists, tuples, dictionaries,sets,strings are all iterable objects. They are iterable containers which
it can get an iterator from.
All these objects have a iter() method which is used to get an iterator:
mytuple=("apple", "banana", "cherry")
myit= iter(mytuple)
print(next(myit))
print(next(myit))
print(next(myit))
OR
my = ("apple", "banana", "cherry")
for x in my:

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print(x)
o/p
apple
banana
Cherry
• Create an Iterator
class MyNumbers:
def __iter__(self):
self.a= 1
return self
def __next__(self):
x=self.a
self.a+= 1
return x
myclass=MyNumbers()
myiter=iter(myclass)
print(next(myiter))
print(next(myiter))
print(next(myiter))
print(next(myiter))
print(next(myiter))
• StopIteration
class MyNumbers:
def __iter__(self):
self.a= 1
return self
def __next__(self):
if self.a<= 20:
x=self.a

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self.a+= 1
return x
else:
raise StopIteration
myclass= MyNumbers()
myiter=iter(myclass)
for x in myiter:
print(x)
Iterator Generator
Class is used to implement an iterator Function is used to implement a
generator.
Local Variables aren’t used. Generator saves the state of the
local variable every time ‘yield’
pauses the loop in python.
Iterators are used mostly to iterate or convert
other objects to an iterator using iter()
function.
Generators are mostly used in
loops to generate an iterator by
returning all the values in the
loop without affecting the
iteration of the loop
Iterator uses iter() and next() functions Generator uses yield keyword
Every iterator is not a generator Every generator is an iterator

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Iterator Generator
my = ("apple", "banana", "cherry")
for x in my:
print(x)
def gen():
yield 1
yield 2
yield 3
for i in gen():
print(i)
Q.Python Classes/Objects
Python is also an object-oriented language.
It support following features
o Class
o Object
o Method
o Inheritance
o Polymorphism
o Data Abstraction
o Encapsulation
Creation of class & object
Syntax
class ClassName:
<statement-1>
.
.
<statement-N>
Syntax
Objectname=classname(aguments)

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e.g 1
class Person:
def __init__(self):#constrcutor
self.name=“amol”
self.age = 36
def myfunc(self):
print("name is " + self.name)
print("age is " + self.age)
p1=Person() #instance_creation
print(p1.name)
print(p1.age)
e.g 2
class Person:
def __init__(self,name,age): #constrcutor
self.name=name
self.age = age
def myfunc(self):
print("name is " + self.name)
print("age is " + self.age)
p1=Person("amol", 36) #instance creation
print(p1.name)
print(p1.age)
self parameter
• The self parameter is a reference to the current instance of the class and It is used
to access attribute of the class.

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• It has to be the first parameter of any function in the class.
• Python will automatically send a reference to the instance. It can capture the of the
instance with any variable name(self).
Constructor
• A constructor is a special type of method (function) that is called automatically
whenever an object of that class is created.
• A constructor is a special type of method (function) which is used to initialize the
instance members of the class.
• The name of constructor is always name _init()_
• Constructors can be of non-parametrized & parameterized.
e.g
1.non-parametrized
class Person:
def __init__(self): #constrcutor
self.name=“amol”
self.age = 36
p1 = Person()
e.g
2 parameterized
class Person:
def __init__(self,name,age): #constrcutor

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self.name=name
self.age = age
p1 = Person("amol", 36)
Garbage collection
• Python deletes unwanted objects (built-in types or class instances) automatically to free
the memory space. The process by which Python periodically frees and reclaims blocks
of memory that no longer are in use is called Garbage Collection.
• Python's garbage collector runs during program execution when an object's reference
count reaches zero.
• An object's reference count increases when it is assigned a new name or placed value.
The object's reference count decreases when it's deleted with del, its reference is
reassigned, or its reference goes out of scope. When an object's reference count reaches
zero, Python collects it automatically.
a = 40 # Create object <40>
b = a # Increase ref. count of <40>
d=b # Increase ref. count of <40>
c = [b] # Increase ref. count of <40>
del a # Decrease ref. count of <40>
b = 100 # Decrease ref. count of <40>
c[0] = -1 # Decrease ref. count of <40>
d=none # Decreases ref. count of <40>
Destructor
• The __del__() method is a known as a destructor method in Python.
• when the object is destroyed, due to garbage collection, then _del_ method is called.
• This method might be used to clean up any non memory resources used by an instance
Syntax
def __del__(self):
# body of destructor

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class SomeObj:
def __init__(self):
print('The object is created.')
def __del__(self):
print('The object is destroyed.')
obj1 = SomeObj()
obj2 = obj1
obj3 = obj1
print("Set obj1 to None...")
obj1 = None
obj2 = None
obj3 = None
Method Overloading
python does not support method overloading by default. But there are different ways to
achieve method overloading in Python.
The problem with method overloading in Python is that it may overload the methods but can
only use the latest defined method.
def product(a, b):
p = a * b
print(p)
# Second product method
# Takes three argument and print their
# product
def product(a, b, c):
p = a * b*c
print(p)

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Python Notes
# Uncommenting the below line shows an error
# product(4, 5)
# This line will call the second product method
product(4, 5, 5)
Operator Overloading
Python support operator overloading.
class Point:
def __init__(self, x=0, y=0):
self.x = x
self.y = y
def __str__(self):
return "({0},{1})".format(self.x, self.y)
def __add__(self, other):
x = self.x + other.x
y = self.y + other.y
return Point(x, y)
p1 = Point(1, 2)
p2 = Point(2, 3)
p3=p1+p2 #p3=p1.__add__(p2)
print(p3)

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Python Notes
List of special method of operator overloading
Python Inheritance
Inheritance allows us to define a class that inherits all the methods and properties from another
class.
Parent class is the class being inherited from, also called base class.
Child class is the class that inherits from another class, also called derived class.
Type of inheritance
1.Single Inheritance: A derived class is inherited from the only one base class known as
Single inheritance .
Syntax
class derived-class(base class):
<class-suite>
e.g

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class A:
def disp1(self):
print("disp1 method in base")
class B(A):
def disp2(self):
print("disp2 method in derived")
ob = B()
ob.disp1()
ob.disp2()
Using Constructor(super keyword)
class A:
def __init__(self,a):
self.a=a
class B(A):
def __init__(self,a,b):
super().__init__(a)
self.b=b
def disp(self):
print("a is",self.a)
print("b is",self.b)
ob=B(1,2)
ob.disp()
2.MultiLevel Inheritance: Multi-level inheritance is archived when a derived class inherits
another derived class.
Syntax
class class1:
<class-suite>
class class2(class1):

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<class suite>
class class3(class2):
<class suite>
e.g
class A:
def disp1(self):
class B(A):
def disp2(self):
print("disp2 method in derived1")
class C(B):
def disp3(self):
ob = C()
ob.disp1()
ob.disp2()
ob.disp3()
3.Multiple inheritance: To inherit multiple base classes in the child class known as multiple
inheritance.
Syntax
class Base1:
<class-suite>
class Base2:
<class-suite>
class BaseN:
<class-suite>

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class Derived(Base1, Base2, ...... BaseN):
<class-suite>
e.g
class A:
def disp1(self):
class B:
def disp2(self):
class C(A,B):
def disp3(self):
ob = C()
ob.disp1()
ob.disp2()
ob.disp3()
Hierarchical Inheritance
Hierarchical inheritance involves more then derived classes derived from the single base or
parent class.
class A:
def disp1(self):
class B(A):
def disp2(self):
class C(A):
def disp3(self):
A
C
B

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ob1 = B()
ob1.disp1()
ob1.disp2()
ob2=C()
ob2.disp1()
ob2.disp3()
Base Class Constructor

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Access Specifier

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public(By
Deafult)
The members
declared as Public
are accessible
from outside the
Class through an
object of the class
class Student:
def __init__(self,rollno,name):
self.rollno=rollno
self.name=name
class Result(Student):
def disp(self):
print("rollno is ",self.rollno)
print("name is ",self.name)
ob=Result(1,"om")
ob.disp()
Private
__(Double
underscore) to
a variable
name makes
it private
The members
declared as
Protected are
accessible from
outside the class
but only in a class
derived from it
that is in the child
or subclass
class Student:
self.__rollno=rollno
self.__name=name
def disp(self):
print("rollno is ",self.__rollno)
print("name is ",self.__name)
ob=Result(1,"om")
ob.disp()
o/p error
Protected
_(single
underscore) to
a variable
name makes
it protected
These members
are only accessible
from within the
class. No outside
Access is allowed.
class Student:
self._rollno=rollno
self._name=name
def disp(self):
print("rollno is ",self._rollno)
print("name is ",self._name)
ob=Result(1,"om")
ob.disp()

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Python Notes
Method Overriding
When the parent class method is redefined in their child class with same name with same
prototype, then the concept is called method overriding.
class A:
def func1(self):
print("this is function 1")
class B(A):
def func1(self):
super().func1()
print("this is function 2")
ob = B()
ob.func1()
Class or Static Variables
• Class or Static variables are the variables that belong to the class and not to objects.
• Class or Static variables are shared amongst objects of the class.
• All variables which are assigned a value in the class declaration are class variables.
And variables which are assigned values inside class methods are instance
variables.
class Student:
stream = 'computer' # Class Variable
def __init__(self,name,roll):
self.name = name # Instance Variable
self.roll = roll # Instance Variable
a = Student('amol', 1)
b = Student('punit', 2)
print(a.stream) # prints "computer"

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Python Notes
print(b.stream) # prints "computer"
print(a.name) # prints "amol"
print(b.name) # prints "punit"
print(a.roll) # prints "1"
print(b.roll) # prints "2"
# Class variables can be accessed using class
# name also
print(Student.stream) # prints "computer"
# Now if we change the stream for just a it won't be changed for b
a.stream = 'computer sci'
print(a.stream) # prints 'computer sci'
print(b.stream) # prints 'computer'
# To change the stream for all instances of the class we can change it
# directly from the class
CSStudent.stream = 'comp'
print(a.stream) # prints 'comp'
print(b.stream) # prints 'comp’
Class Method & Static Method
Class Method Static Method
The class method takes cls (class) as first argument. The static method does not take any specific parameter.
Class method can access and modify the class state.
i.e
It can access class attributes
Static Method cannot access or modify the class state.
i.e
It cannot access either class attributes or instance
attributes.

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The class method takes the class as parameter to know
about the state of that class.
Static methods do not know about class state. These
methods are used to do some utility tasks by taking some
parameters.
@classmethod decorator is used here. @staticmethod decorator is used here.
It can be called using
the ClassName.MethodName() or object.MethodName().
It can be called using
the ClassName.MethodName() or object.MethodName().
class my_class:
@classmethod
def function_name(cls, arguments):
#Function Body
return value
class my_class:
@staticmethod
def function_name(arguments):
#Function Body
return value

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Python Notes
Python Exception
Definition:
An exception is an event, which occurs during the execution of a program that disrupts the
normal flow of the program's instructions.
List of Standard Exceptions −
Sr.No. Exception Name & Description
1 Exception
Base class for all exceptions
2 StopIteration
Raised when the next() method of an iterator does not point to any
object.
3 SystemExit
Raised by the sys.exit() function.
4 StandardError
Base class for all built-in exceptions except StopIteration and
SystemExit.
5 ArithmeticError
Base class for all errors that occur for numeric calculation.
6 OverflowError
Raised when a calculation exceeds maximum limit for a numeric type.
7 FloatingPointError
Raised when a floating point calculation fails.
8 ZeroDivisionError
Raised when division or modulo by zero takes place for all numeric
types.
9 AssertionError
Raised in case of failure of the Assert statement.

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10 AttributeError
Raised in case of failure of attribute reference or assignment.
11 EOFError
Raised when there is no input from either the raw_input() or input()
function and the end of file is reached.
12 ImportError
Raised when an import statement fails.
13 KeyboardInterrupt
Raised when the user interrupts program execution, usually by pressing
Ctrl+c.
14 LookupError
Base class for all lookup errors.
15 IndexError
Raised when an index is not found in a sequence.
16 KeyError
Raised when the specified key is not found in the dictionary.
17 NameError
Raised when an identifier is not found in the local or global namespace.
18 UnboundLocalError
Raised when trying to access a local variable in a function or method
but no value has been assigned to it.
19 EnvironmentError
Base class for all exceptions that occur outside the Python
environment.
20 IOError
Raised when an input/ output operation fails, such as the print
statement or the open() function when trying to open a file that does
not exist.
21 IOError
Raised for operating system-related errors.

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22 SyntaxError
Raised when there is an error in Python syntax.
23 IndentationError
Raised when indentation is not specified properly.
24 SystemError
Raised when the interpreter finds an internal problem, but when this
error is encountered the Python interpreter does not exit.
25 SystemExit
Raised when Python interpreter is quit by using the sys.exit() function.
If not handled in the code, causes the interpreter to exit.
26 TypeError
Raised when an operation or function is attempted that is invalid for
the specified data type.
27 ValueError
Raised when the built-in function for a data type has the valid type of
arguments, but the arguments have invalid values specified.
28 RuntimeError
Raised when a generated error does not fall into any category.
29 NotImplementedError
Raised when an abstract method that needs to be implemented in an
inherited class is not actually implemented.
Handling an exception
The try: block contains one or more statements which are likely to encounter an exception.
If the statements in this block are executed without an exception, the subsequent except:
block is skipped.
If the exception does occur, the program flow is transferred to the except: block.
The else keyword to define a block of code to be executed if no errors were raised

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Syntax
try:
You do your operations here;
......................
except ExceptionI:
If there is ExceptionI, then execute this block.
except ExceptionII:
If there is ExceptionII, then execute this block.
......................
else:
If there is no exception then execute this block.
e.g
try:
x=int(input('Enter a number: '))
y=int(input('Enter another number: '))
z=x/y
except ZeroDivisionError:
print("Division by 0 not accepted")
else:
print("else block")
e.g 2 Handles all types of exception
try:
z=x/y
except Exception:
else:
print("else block")
except Clause with Multiple Exceptions
Syntax
try:
......................
except(Exception1[, Exception2[,...ExceptionN]]]):

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If there is any exception from the given exception list,
then execute this block.
......................
else:
If there is no exception then execute this block.
e.g
try:
z=x/y
except (ArithmeticError,ZeroDivisionError):
else:
print("else block")
Finally Block
The finally block, if specified, will be executed regardless if the try block raises an error or not.
Syntax
try:
......................
Due to any exception, this may be skipped.
finally:
This would always be executed.
e.g
try:
z=x/y
except ZeroDivisionError:
finally:
print("finally block")

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Raise an exception
Python also provides the raise keyword to be used throw an exception to be explicitly.
Syntax
raise [Exception [, args]
Where
Exception :It is the type of exception (for example, NameError)
Argument: It is a value for the exception argument.
try:
x=int(input('Enter a number upto 100: '))
if x > 100:
raise ValueError(x)
except ValueError:
print(x, "is out of allowed range")
else:
print(x, "is within the allowed range")
User-defined Exceptions
e.g
class Myerror(Exception):
def __init__(self,arg):
self.arg=arg
try:
n=int(input("enter value"))
if(n<0):
raise Myerror("no is negative")
else:
print("postive value")
except Myerror as e:
print (e.arg)

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Python Notes
What is Assertion?
The assert keyword is used for debugging code. assert statement has a condition or expression
which is supposed to be always true. If the condition is false assert halts the program and gives
an AssertionError.
Syntax
assert <condition>
assert <condition>,<error message>
e.g 1.Assert using without error
x = "vision"
assert x == "goodbye"
print("both strings are same")
o/p AssertionError
e.g 2.Assert using without error
x = "goodbye"
#if condition returns False, AssertionError is
raised:
assert x == "goodbye"
o/p both strings are same
Eg. 3 Assert using error
x = "vision"
raised:
Eg.4 Assert using error
x = "goodbye"
raised:

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assert x == "goodbye", "both strings are
same'"
o/p
assert x == "goodbye", "both strings are not
same"
AssertionError: both strings are not same
assert x == "goodbye", "both strings are not
same"
o/p both strings are same

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Q.Python Modules
A python module can be defined as a python program file which contains a python code
including python functions, class, or variables. In other words, we can say that our python
code file saved with the extension (.py) is treated as the module
module to be the same as a code library
To creation of User Defined package
1.To create module
def show(name):
print("Hello, " + name)
Note: save as mymodule.py
2. The import Statement
It can use any Python source file as a module by executing an import statement in some other
Python source file.
syntax −
import module1[, module2[,... moduleN]
import mymodule
mymodule.show("om")
e.g To add some part in above module
person1={
"name": "om",
"age": 22,
"country": "india"
}

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save above code in mymodule.py
import mymodule
a=mymodule.person1["age"]
print(a)
Import From Module
It can choose to import only parts from a module, by using the from keyword.
from modname import name1[, name2[, ... nameN]]
def show(name):
print("Hello," +name)
person1={
"name": "om",
"age": 22,
"country": "india"
}
Import only the person1 dictionary from the module
from mymodule import person1
print (person1["age"])
from...import * Statement

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It is also possible to import all names from a module into the current namespace by using the
following import statement
from mymodule import *
print (person1["age"])
show("om")
Re-naming a Module
It can create an alias when it import a module, by using the as keyword
import mymodule as mx
a=mx.person1["age"]
print(a)
Pre defined module
import calendar
cal = calendar.month(2021, 1)
print ("Here is the calendar:")
print (cal)
#current date & time
import datetime
x = datetime.datetime.now()
print(x)

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Tkinter(GUI) Programming
Python provides the standard library Tkinter for creating the graphical user interface for
desktop based applications.
• Tkinter top-level window can be created by using the following steps.
1. import the Tkinter module.
2. Create the main application window.
3. Add the widgets like labels, buttons, frames, etc. to the window.
4. Call the main event loop so that the actions can take place on the user's computer
screen.
• Creating the application main window.
from tkinter import *
parent = Tk()
parent.mainloop() # It is similar to getch() or infinite loop

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• Geometry Management
All Tkinter widgets have access to specific geometry management methods, which
have the purpose of organizing widgets throughout the parent widget area. Tkinter
exposes the following geometry manager classes: pack, grid, and place.
1.Pack()
This geometry manager organizes widgets in blocks before placing them in the parent widget.
Syntax
widget.pack(options )
Here is the list of possible options −
• expand − When set to true, widget expands to fill any space not otherwise used in
widget's parent.
• fill − Determines whether widget fills any extra space allocated to it by the packer, or
keeps its own minimal dimensions: NONE (default), X (fill only horizontally), Y (fill
only vertically), or BOTH (fill both horizontally and vertically).
• side − Determines which side of the parent widget packs against: TOP (default),
BOTTOM, LEFT, or RIGHT.
e.g
redbutton = Button(parent, text = "Red", fg = "red")
redbutton.pack( side = LEFT)
2.grid method
The grid() geometry manager organizes the widgets in the tabular form. We can specify the
rows and columns as the options in the method call. We can also specify the column span
(width) or rowspan(height) of a widget.

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Syntax
widget.grid(options)
A list of possible options that can be passed inside the grid() method is given below.
o Column
The column number in which the widget is to be placed. The leftmost column is
represented by 0.
o Columnspan
The width of the widget. It represents the number of columns up to which, the column
is expanded.
o ipadx,ipady
It represents the number of pixels to pad the widget inside the widget's border.
o padx,pady
It represents the number of pixels to pad the widget outside the widget's border.
o row
The row number in which the widget is to be placed. The topmost row is represented
by 0.
o rowspan
The height of the widget, i.e. the number of the row up to which the widget is expanded.
o Sticky
If the cell is larger than a widget, then sticky is used to specify the position of the widget
inside the cell. It may be the concatenation of the sticky letters representing the position
of the widget. It may be N, E, W, S, NE, NW, NS, EW, ES.
b = 0
for r in range(6):
for c in range(6):
b = b + 1
Button(parent, text = str(b), borderwidth = 1 ).grid(row = r,column = c)

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3.place() method
The place() geometry manager organizes the widgets to the specific x and y coordinates.
Syntax
widget.place(options)
A list of possible options is given below.
o Anchor: It represents the exact position of the widget within the container. The default
value (direction) is NW (the upper left corner)
o bordermode: The default value of the border type is INSIDE that refers to ignore the
parent's inside the border. The other option is OUTSIDE.
o height, width: It refers to the height and width in pixels.

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o relheight, relwidth: It is represented as the float between 0.0 and 1.0 indicating the
fraction of the parent's height and width.
o relx, rely: It is represented as the float between 0.0 and 1.0 that is the offset in the
horizontal and vertical direction.
o x, y: It refers to the horizontal and vertical offset in the pixels.
password = Label(parent, text = "Password").place(x = 30, y = 130)
• Tkinter widgets
There are various widgets like button, canvas, checkbutton, entry, etc. that are used to
build the python GUI applications.
1.Label
The Label is used to specify the container box where we can place the text or images. This
widget is used to provide the message to the user about other widgets used in the python
application.
Syntax
w = Label (parent, options)
SN Option Description
1 anchor It specifies the exact position of the text within the size provided to
the widget. The default value is CENTER, which is used to center
the text within the specified space.
2 bg The background color displayed behind the widget.
3 bitmap It is used to set the bitmap to the graphical object specified so that,
the label can represent the graphics instead of text.

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4 bd It represents the width of the border. The default is 2 pixels.
5 cursor The mouse pointer will be changed to the type of the cursor
specified, i.e., arrow, dot, etc.
6 font The font type of the text written inside the widget.
7 fg The foreground color of the text written inside the widget.
8 height The height of the widget.
9 image The image that is to be shown as the label.
10 justify It is used to represent the orientation of the text if the text contains
multiple lines. It can be set to LEFT for left justification, RIGHT for
right justification, and CENTER for center justification.
11 padx The horizontal padding of the text. The default value is 1.
12 pady The vertical padding of the text. The default value is 1.
13 relief The type of the border. The default value is FLAT.
14 text This is set to the string variable which may contain one or more line
of text.
15 textvariable The text written inside the widget is set to the control variable
StringVar so that it can be accessed and changed accordingly.
16 underline We can display a line under the specified letter of the text. Set this
option to the number of the letter under which the line will be
displayed.
17 width The width of the widget. It is specified as the number of characters.
18 wraplength Instead of having only one line as the label text, we can break it to
the number of lines where each line has the number of characters
specified to this option.

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parent = Tk()
parent.geometry("400x250")
uname = Label(parent, text = "Username",bg="red").place(x = 30,y = 50)
parent.mainloop()
2. Entry
The Entry widget is used to provde the single line text-box to the user to accept a value from
the user. We can use the Entry widget to accept the text strings from the user. It can only be
used for one line of text from the user. For multiple lines of text, we must use the text widget.
Syntax
w = Entry (parent, options)
1 Bg The background color of the widget.
2 Bd The border width of the widget in pixels.
3 Cursor The mouse pointer will be changed to the cursor type set to the
arrow, dot, etc.
4 Exportselection The text written inside the entry box will be automatically
copied to the clipboard by default. We can set the
exportselection to 0 to not copy this.
5 Fg It represents the color of the text.
6 Font It represents the font type of the text.
7 highlightbackground It represents the color to display in the traversal highlight region
when the widget does not have the input focus.

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8 Highlightcolor It represents the color to use for the traversal highlight rectangle
that is drawn around the widget when it has the input focus.
9 Highlightthickness It represents a non-negative value indicating the width of the
highlight rectangle to draw around the outside of the widget
when it has the input focus.
10 Insertbackground It represents the color to use as background in the area covered
by the insertion cursor. This color will normally override either
the normal background for the widget.
11 Insertborderwidth It represents a non-negative value indicating the width of the 3-
D border to draw around the insertion cursor. The value may
have any of the forms acceptable to Tk_GetPixels.
12 Insertofftime It represents a non-negative integer value indicating the number
of milliseconds the insertion cursor should remain "off" in each
blink cycle. If this option is zero, then the cursor doesn't blink:
it is on all the time.
13 Insertontime Specifies a non-negative integer value indicating the number of
milliseconds the insertion cursor should remain "on" in each
blink cycle.
14 Insertwidth It represents the value indicating the total width of the insertion
cursor. The value may have any of the forms acceptable to
Tk_GetPixels.
15 Justify It specifies how the text is organized if the text contains multiple
lines.
16 Relief It specifies the type of the border. Its default value is FLAT.
17 Selectbackground The background color of the selected text.
18 Selectborderwidth The width of the border to display around the selected task.
19 selectforeground The font color of the selected task.
20 show It is used to show the entry text of some other type instead of the
string. For example, the password is typed using stars (*).

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21 textvariable It is set to the instance of the StringVar to retrieve the text from
the entry.
22 width The width of the displayed text or image.
23 xscrollcommand The entry widget can be linked to the horizontal scrollbar if we
want the user to enter more text then the actual width of the
widget.
Methods
SN Method Description
1 delete(first, last = none) It is used to delete the specified characters inside the widget.
2 get() It is used to get the text written inside the widget.
3 icursor(index) It is used to change the insertion cursor position. We can
specify the index of the character before which, the cursor
to be placed.
4 index(index) It is used to place the cursor to the left of the character
written at the specified index.
5 insert(index,s) It is used to insert the specified string before the character
placed at the specified index.
6 select_adjust(index) It includes the selection of the character present at the
specified index.
7 select_clear() It clears the selection if some selection has been done.
8 select_form(index) It sets the anchor index position to the character specified by
the index.

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9 select_present() It returns true if some text in the Entry is selected otherwise
returns false.
10 select_range(start,end) It selects the characters to exist between the specified range.
11 select_to(index) It selects all the characters from the beginning to the
specified index.
12 xview(index) It is used to link the entry widget to a horizontal scrollbar.
13 xview_scroll(number,what) It is used to make the entry scrollable horizontally.
e1 = Entry(parent).place(x = 80, y = 50)
e2 = Entry(parent,show="*").place(x = 80, y = 50)
3.Button
The button widget is used to add various types of buttons to the python application.
Syntax
W = Button(parent, options)
1 activebackground It represents the background of the button when the mouse hover the
button.
2 activeforeground It represents the font color of the button when the mouse hover the
button.
3 Bd It represents the border width in pixels.
4 Bg It represents the background color of the button.

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5 Command It is set to the function call which is scheduled when the function is
called.
6 Fg Foreground color of the button.
7 Font The font of the button text.
8 Height The height of the button. The height is represented in the number of
text lines for the textual lines or the number of pixels for the images.
10 Highlightcolor The color of the highlight when the button has the focus.
11 Image It is set to the image displayed on the button.
12 justify It illustrates the way by which the multiple text lines are represented.
It is set to LEFT for left justification, RIGHT for the right
justification, and CENTER for the center.
13 Padx Additional padding to the button in the horizontal direction.
14 pady Additional padding to the button in the vertical direction.
15 Relief It represents the type of the border. It can be SUNKEN, RAISED,
GROOVE, and RIDGE.
17 State This option is set to DISABLED to make the button unresponsive.
The ACTIVE represents the active state of the button.
18 Underline Set this option to make the button text underlined.
19 Width The width of the button. It exists as a number of letters for textual
buttons or pixels for image buttons.
20 Wraplength If the value is set to a positive number, the text lines will be wrapped
to fit within this length.
e.g 1.
b = Button(parent,text = "OK").place(x=80,y=50)

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e.g2
parent = Tk()
def fun():
msg=Message(parent, text = "Welcome").pack()
b=Button(parent, text ="OK", command = fun).pack()
parent.mainloop()
e.g3
Addition of two number
from functools import partial
def call_result(label_result, n1, n2):
num1 = (n1.get())
num2 = (n2.get())
result = int(num1)+int(num2)
label_result.config(text="Result = %d" % result)
return
parent = Tk()
parent.geometry('400x200+100+200')
parent.title('Calculator')
number1 = StringVar()
number2 = StringVar()
labelNum1 = Label(parent, text="A").grid(row=1, column=0)
labelNum2 = Label(parent, text="B").grid(row=2, column=0)
labelResult = Label(parent)
labelResult.grid(row=7, column=2)
entryNum1 = Entry(parent, textvariable=number1).grid(row=1, column=2)

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entryNum2 = Entry(parent, textvariable=number2).grid(row=2, column=2)
callr = partial(call_result,labelResult, number1, number2)
buttonCal = Button(parent, text="Calculate", command=callr).grid(row=6, column=0)
parent.mainloop()
Note: In command ,yu can’t calling function using arguments, so it used lemda
or partial function.
3. Frame
Python Tkinter Frame widget is used to organize the group of widgets. It acts like a container
which can be used to hold the other widgets. The rectangular areas of the screen are used to
organize the widgets to the python application.
Syntax
w = Frame(parent, options)
1 Bd It represents the border width.
3 Cursor The mouse pointer is changed to the cursor type set to different
values like an arrow, dot, etc.
4 Height The height of the frame.
5 highlightbackground The color of the background color when it is under focus.
6 Highlightcolor The text color when the widget is under focus.

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7 highlightthickness It specifies the thickness around the border when the widget is
under the focus.
8 Relief It specifies the type of the border. The default value if FLAT.
9 Width It represents the width of the widget.
parent = Tk()
frame = Frame(parent)
frame.pack()
bottomframe = Frame(parent)
bottomframe.pack( side = BOTTOM )
redbutton = Button(frame, text="Red", fg="red")
redbutton.pack( side = LEFT)
greenbutton = Button(frame, text="Brown", fg="brown")
greenbutton.pack( side = LEFT )
bluebutton = Button(frame, text="Blue", fg="blue")
bluebutton.pack( side = LEFT )
blackbutton = Button(bottomframe, text="Black", fg="black")
blackbutton.pack( side = BOTTOM)

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parent.mainloop()
4.messagebox
The messagebox module is used to display the message boxes in the python applications. There
are the various functions which are used to display the relevant messages depending upon the
application requirements.
Syntax
messagebox.function_name(title, message [, options])
Parameters
o function_name: It represents an appropriate message box function.
o title: It is a string which is shown as a title of a message box.
o message: It is the string to be displayed as a message on the message box.
o options: There are various options which can be used to configure the message dialog
box.
The two options that can be used are default and parent.
1. default
o The default option is used to mention the types of the default button, i.e. ABORT,
RETRY, or IGNORE in the message box.
2. parent
o The parent option specifies the parent window on top of which, the message box is to
be displayed.
You could use one of the following functions with dialogue box .

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1. showinfo()
2. showwarning()
3. showerror()
4. askquestion()
5. askokcancel()
6. askyesno()
7. askretrycancel()
e.g
from tkinter import messagebox
parent = Tk()
messagebox.showinfo("information","Information")
parent.mainloop()
5.Checkbutton
The Checkbutton widget is used to display a number of options to a user as toggle buttons.
The user can then select one or more options by clicking the button corresponding to each
option.
Syntax
w = checkbutton(master, options)

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1 activebackground It represents the background color when the checkbutton is
under the cursor.
2 activeforeground It represents the foreground color of the checkbutton when the
checkbutton is under the cursor.
3 Bg The background color of the button.
4 Bitmap It displays an image (monochrome) on the button.
5 Bd The size of the border around the corner.
6 Command It is associated with a function to be called when the state of the
checkbutton is changed.
7 Cursor The mouse pointer will be changed to the cursor name when it
is over the checkbutton.
8 disableforeground It is the color which is used to represent the text of a disabled
checkbutton.
9 Font It represents the font of the checkbutton.
10 Fg The foreground color (text color) of the checkbutton.
11 Height It represents the height of the checkbutton (number of lines).
The default height is 1.
12 Highlightcolor The color of the focus highlight when the checkbutton is under
focus.
13 Image The image used to represent the checkbutton.
14 Justify This specifies the justification of the text if the text contains
multiple lines.
15 Offvalue The associated control variable is set to 0 by default if the
button is unchecked. We can change the state of an unchecked
variable to some other one.
16 Onvalue The associated control variable is set to 1 by default if the
button is checked. We can change the state of the checked
variable to some other one.

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17 Padx The horizontal padding of the checkbutton
18 Pady The vertical padding of the checkbutton.
19 Relief The type of the border of the checkbutton. By default, it is set
to FLAT.
20 Selectcolor The color of the checkbutton when it is set. By default, it is red.
21 Selectimage The image is shown on the checkbutton when it is set.
22 State It represents the state of the checkbutton. By default, it is set to
normal. We can change it to DISABLED to make the
checkbutton unresponsive. The state of the checkbutton is
ACTIVE when it is under focus.
24 Underline It represents the index of the character in the text which is to be
underlined. The indexing starts with zero in the text.
25 Variable It represents the associated variable that tracks the state of the
checkbutton.
26 Width It represents the width of the checkbutton. It is represented in
the number of characters that are represented in the form of
texts.
27 Wraplength If this option is set to an integer number, the text will be broken
into the number of pieces.
Methods
The methods that can be called with the Checkbuttons are described in the following table.
1 deselect() It is called to turn off the checkbutton.
2 flash() The checkbutton is flashed between the active and normal
colors.

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3 invoke() This will invoke the method associated with the checkbutton.
4 select() It is called to turn on the checkbutton.
5 toggle() It is used to toggle between the different Checkbuttons.
top = Tk()
top.geometry("200x200")
checkvar1 = IntVar()
checkvar2 = IntVar()
chkbtn1 = Checkbutton(top, text = "C", variable = checkvar1, onvalue = 1, offvalue = 0,
height = 2, width = 10)
chkbtn2 = Checkbutton(top, text = "C++", variable = checkvar2, onvalue = 1, offvalue = 0,
height = 2, width = 10)
chkbtn1.pack()
chkbtn2.pack()
top.mainloop()
6. Radiobutton
The Radiobutton widget is used to implement one-of-many selection in the python application.
It shows multiple choices to the user out of which, the user can select only one out of them.
Syntax
w = Radiobutton(top, options)
1 activebackground The background color of the widget when it has the focus.
2 activeforeground The font color of the widget text when it has the focus.

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3 Anchor It represents the exact position of the text within the
widget if the widget contains more space than the
requirement of the text. The default value is CENTER.
5 Bitmap It is used to display the graphics on the widget. It can be
set to any graphical or image object.
6 borderwidth It represents the size of the border.
7 command This option is set to the procedure which must be called
every-time when the state of the radiobutton is changed.
8 Cursor The mouse pointer is changed to the specified cursor
type. It can be set to the arrow, dot, etc.
9 Font It represents the font type of the widget text.
10 Fg The normal foreground color of the widget text.
11 Height The vertical dimension of the widget. It is specified as the
number of lines (not pixel).
12 highlightcolor It represents the color of the focus highlight when the
widget has the focus.
13 highlightbackground The color of the focus highlight when the widget is not
having the focus.
14 Image It can be set to an image object if we want to display an
image on the radiobutton instead the text.
15 Justify It represents the justification of the multi-line text. It can
be set to CENTER(default), LEFT, or RIGHT.
16 Padx The horizontal padding of the widget.
17 Pady The vertical padding of the widget.
18 Relief The type of the border. The default value is FLAT.

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19 selectcolor The color of the radio button when it is selected.
20 selectimage The image to be displayed on the radiobutton when it is
selected.
21 State It represents the state of the radio button. The default state
of the Radiobutton is NORMAL. However, we can set
this to DISABLED to make the radiobutton
unresponsive.
22 Text The text to be displayed on the radiobutton.
23 textvariable It is of String type that represents the text displayed by
the widget.
24 underline The default value of this option is -1, however, we can set
this option to the number of character which is to be
underlined.
25 Value The value of each radiobutton is assigned to the control
variable when it is turned on by the user.
26 Variable It is the control variable which is used to keep track of the
user's choices. It is shared among all the radiobuttons.
27 Width The horizontal dimension of the widget. It is represented
as the number of characters.
28 wraplength We can wrap the text to the number of lines by setting
this option to the desired number so that each line
contains only that number of characters.
1 deselect() It is used to turn of the radiobutton.
2 flash() It is used to flash the radiobutton between its active and normal colors few
times.
3 invoke() It is used to call any procedure associated when the state of a Radiobutton is
changed.

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4 select() It is used to select the radiobutton.
e.g
def sel():
selection = "You selected the option " + str(var.get())
label.config(text = selection)
parent = Tk()
var = IntVar()
R1 = Radiobutton(parent, text="BCS", variable=var, value=1,command=sel)
R1.pack()
R2 = Radiobutton(parent, text="BBA", variable=var, value=2,command=sel)
R2.pack()
R3 = Radiobutton(parent, text="BCA", variable=var, value=3,command=sel)
R3.pack()
label = Label(parent)
label.pack()
parent.mainloop()
7.Listbox
The Listbox widget is used to display the list items to the user. We can place only text items in
the Listbox and all text items contain the same font and color.
The user can choose one or more items from the list depending upon the configuration.

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Syntax
w = Listbox(parent, options)
1 bg The background color of the widget.
2 bd It represents the size of the border. Default value is 2 pixel.
3 cursor The mouse pointer will look like the cursor type like dot, arrow, etc.
4 font The font type of the Listbox items.
5 fg The color of the text.
6 height It represents the count of the lines shown in the Listbox. The default
value is 10.
7 highlightcolor The color of the Listbox items when the widget is under focus.
8 highlightthickness The thickness of the highlight.
9 relief The type of the border. The default is SUNKEN.
10 selectbackground The background color that is used to display the selected text.
11 selectmode It is used to determine the number of items that can be selected from
the list. It can set to BROWSE, SINGLE, MULTIPLE, EXTENDED.
12 width It represents the width of the widget in characters.
13 xscrollcommand It is used to let the user scroll the Listbox horizontally.
14 yscrollcommand It is used to let the user scroll the Listbox vertically.
Methods

127 Vision Academy
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Python Notes
1 activate(index) It is used to select the lines at the specified index.
2 curselection() It returns a tuple containing the line numbers of the
selected element or elements, counting from 0. If nothing
is selected, returns an empty tuple.
3 delete(first, last = None) It is used to delete the lines which exist in the given range.
4 get(first, last = None) It is used to get the list items that exist in the given range.
5 index(i) It is used to place the line with the specified index at the
top of the widget.
6 insert(index, *elements) It is used to insert the new lines with the specified number
of elements before the specified index.
7 nearest(y) It returns the index of the nearest line to the y coordinate
of the Listbox widget.
8 see(index) It is used to adjust the position of the listbox to make the
lines specified by the index visible.
9 size() It returns the number of lines that are present in the
Listbox widget.
10 xview() This is used to make the widget horizontally scrollable.
11 xview_moveto(fraction) It is used to make the listbox horizontally scrollable by the
fraction of width of the longest line present in the listbox.
12 xview_scroll(number,
what)
It is used to make the listbox horizontally scrollable by the
number of characters specified.
13 yview() It allows the Listbox to be vertically scrollable.
14 yview_moveto(fraction) It is used to make the listbox vertically scrollable by the
fraction of width of the longest line present in the listbox.
15 yview_scroll (number,
what)
It is used to make the listbox vertically scrollable by the
number of characters specified.

128 Vision Academy
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Python Notes
parent = Tk()
lbl = Label(parent,text = "A list of favourite countries...")
listbox = Listbox(parent)
listbox.insert(1,"India")
listbox.insert(2, "USA")
listbox.insert(3, "Japan")
listbox.insert(4, "Austrelia")
lbl.pack()
listbox.pack()
parent.mainloop()
8.Message
The Message widget is used to show the message to the user regarding the behaviour of the
python application. The message widget shows the text messages to the user which can not be
edited.
The message text contains more than one line.
Syntax
w = Message(parent, options)

129 Vision Academy
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Python Notes
1 anchor It is used to decide the exact position of the text within the space
provided to the widget if the widget contains more space than
the need of the text. The default is CENTER.
2 bg The background color of the widget.
3 bitmap It is used to display the graphics on the widget. It can be set to
any graphical or image object.
4 bd It represents the size of the border in the pixel. The default size
is 2 pixel.
5 cursor The mouse pointer is changed to the specified cursor type. The
cursor type can be an arrow, dot, etc.
6 font The font type of the widget text.
7 fg The font color of the widget text.
8 height The vertical dimension of the message.
9 image We can set this option to a static image to show that onto the
widget.
10 justify This option is used to specify the alignment of multiple line of
code with respect to each other. The possible values can be
LEFT (left alignment), CENTER (default), and RIGHT (right
alignment).
11 padx The horizontal padding of the widget.
12 pady The vertical padding of the widget.
13 relief It represents the type of the border. The default type is FLAT.
14 text We can set this option to the string so that the widget can
represent the specified text.
15 textvariable This is used to control the text represented by the widget. The
textvariable can be set to the text that is shown in the widget.

130 Vision Academy
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Python Notes
16 underline The default value of this option is -1 that represents no
underline. We can set this option to an existing number to
specify that nth letter of the string will be underlined.
17 width It specifies the horizontal dimension of the widget in the
number of characters (not pixel).
18 wraplength We can wrap the text to the number of lines by setting this
option to the desired number so that each line contains only that
number of characters.
top = Tk()
top.geometry("100x100")
var = StringVar()
msg = Message( top, text = "Welcome to Javatpoint")
msg.pack()
top.mainloop()

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