ESIT135 : Unit 1 Python Basics Concepts

By,
Ms. Swapnali S. Gawali,
Asst. Prof. Computer Engineering
Sanjivani College of Engineering, Kopargaon
Sanjivani Rural Education Society’s
Sanjivani College of Engineering, Kopargaon-423 603
Department of Computer Engineering

Department of Computer Engineering, Sanjivani College of Engineering, Kopargaon 2

Problem Solving in everyday life
People make decisions every day to solve problems that
affect their lives
• Important problems
• Unimportant problem
• Bad/Good decision

 There are six steps to follow to ensure the best decision:
1.Identify the problem.
2.Understand the problem
3.Identify alternative ways to solve the problem
4.Select the best way to solve the problem from the list of alternative
solutions
5.List instructions that enable you to solve the problem using the
selected solution
6.Evaluate the solution

 The first step toward solving a problem is to identify the problem
 What is the specific problem? (This means you should determine
what is that you want to change)
 Clearly define the goal that you want to achieve. (What are you
trying to achieve?)
 Determine what are the inputs and outputs
 If you don’t know what the problem is, you cannot solve it.

 You must understand what is involved in the problem before you can
continue toward the solution
 This includes understanding the knowledge base of the person or
machine for whom you are solving the problem
 Also, you also must know your own knowledge base., You cannot
solve a problem if you do not know the subject. For example, to solve
a problem involving accounting, you must know accounting
 You can’t automatically desired the information

 Generate as many potential solutions as possible
 List the features for each possible solution
 You might want to talk to other people to find other solutions than
those you have identified.
 Alternative solutions must be acceptable ones

 In this step, you need to identify and evaluate the pros and cons of
each possible solution before selecting the best one
 In order to do this, you need to select criteria for the evaluation

 These numbered, step-by-step instructions must fall within the
knowledge base set up in step 2
 Do Stage
 Planning: Create a numbered, step-by-step set of instructions

 To evaluate or test a solution means to check its result to see if it is
correct, and to see if it satisfies the needs of the person(s) with the
problem. • Test the solution
 Are the results accurate?
 Does the solution solve the original problem?
 Does it satisfy the needs of the user?
 Is it acceptable to the user?

 The tasks required to solve the problem with Computer, are group into tree phases
 Identify the purpose
 Identifying parameters and constraints
 Collecting information
 Developing a program
 Identifying Logical Structure
 Writing Algorithm
 Drawing Flowchart
 Writing pseudocode
 Writing a computer program
 Debugging the program
 Executing a program

 Python is a popular high-level, interpreted programming language used in various
applications
 Python is an easy language to learn because of its simple syntax
 Python can be used for simple tasks such as plotting or for more complex tasks like
machine learning

 Created in 1990 by Guido van Rossum
 Named after Monty Python
 First public release in 1991
 comp.lang.python founded in 1994
 Open source from the start
 Considered a scripting language, but is much more
 Scalable, object oriented and functional from the beginning
 Used by Google from the beginning
 Increasingly popular

“Python is an experiment in how
much freedom program-mers need.
Too much freedom and nobody can
read another's code; too little and
expressive-ness is endangered.”
- Guido van Rossum

Features of Python
1. Free and
Open Source
2. Easy to
code
3. Easy to
Read 4. Object-Oriented
Language
5. GUI Programming
Support
6. High-Level
Language
7. Portable
8. Easy to
Debug
9. Integrated and
Interpreted
10. Large
Standard Library

 A value is one of the basic things a program work with, like letter or
a number.
 Example:
 2 – Integer
 42.0 – Floating Point
 ‘Hello’ – String
 We use variable to stored value.

 A data type defines the type of data stored in a variable.
 Python is a dynamically typed language, so we do not need to defined
data types while declaring.
 Data types are the classification or categorization of data items.
Data Type
Numeric
Integer Complex
Number
Float
Dictionary Boolean Set Sequence
Strings Tuple
List

 It represent data which has numeric value.
 Three Categories:
 Integer: int
 Float: float
 Complex Number: complex
 Integer: It contains negative and positive whole numbers. (without
decimal or fraction) Example:101,-319,20
 Float: It is real number with floating-point. Example: 1.5,4.5,3.5
 Complex Number: It is specified as (real part)+(imaginary part)j
 example: -2+6j

 It is the ordered collection of similar or different data types.
 Sequences used to stored multiple values in an organized and
efficient fashion.
 Three Categories:
 String: ' '," ",''' '''
 List: [ ]
 Tuple: ()
 String: It is a collection of one or more characters put in ‘single
quote’, “double quote” and ‘‘‘ Triple quote”’

 List: It is like a array, which is ordered collection of data.
 It contains data of different types.
 The items are separated by comma(,) and enclosed with in square
bracket[].
 Example:A
list = [1,2,3,4,5,6]
fruit=["Apple", "mango", "banana"]

 Tuple: It is Like list, it also contains data of different types. The
items are separated by comma(,) and enclosed with in square
bracket().
 Tuple is immutable.
 Example:
fruit=("Apple", "mango", "banana")
tuple= (1,2,3,4,5)

 It provides two built in values, True and False.
 It determine the given value is true or false.
 It is denoted by class ' bool '.
 It also represented by ' 0 ' or ' 1 '
Example:
print(11>9)
a=200, b=33
print(a<b)

 It is unordered collection of the data type.
 It is iterable, mutable and has unique elements.
 In it order of element is undefined.
 It is created by using built-in set() function, or a sequence of
elements is passed in curly braces and separated by comma.
 Example:
my_set = {1,2,3}
myset = {1.0, ' Hi ', (1,2,3,4)}

 It is an unordered set of a key-value pair of items.
 It is like an associative array or hash table where each key stores a
specific value.
 Key can store primitive data types.
 Value is an arbitrary Python Object.
 Example:
thisdict = {' brand ' : ' Maruti ', ' model ' : ' Swift ', ' year ' : 2000}

 Variables are containers for storing data values.
 Unlike other programming languages, Python has no command for declaring a
variable.
 A variable is created the moment we first assign a value to it.
 x = 5
y = "John"
print(x) 5
print(y) John
 Variables do not need to be declared with any particular type and can even change
type after they have been set.
 String variables can be declared either by using single or double quotes: ‘John’
or”John”

 Following are rules for creating variables in Python
1. A variable name must start with a letter or the underscore character.
 example: a, name, _name_
2. A variable name cannot start with a number.
 Example: This is not allowed: 12a
3. A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9,
and _ ).
 Example: Name, a12
4. Variable names are case-sensitive (name, Name and NAME are three different
variables).
 Example: This A is different than a
5. The reserved words(keywords) cannot be used naming the variable.
 Example: This word not allowed
and, assert, break, class, continue, def, del, elif, else, except, exec, finally, for, from,
global, if, import, in, is, not, or, pass, print, raise, return, try, while

 Input is any information provided to the program
– Keyboard input
– Mouse input
– File input
– Sensor
input (microphone, camera, photo cell, etc.)
 Output is any information (or effect) that a program produces:
– sounds, lights, pictures, text, motion, etc.
Output( on a screen, in a file, on a disk or tape, etc.)

 print(): Used to print output.
 Example 1:
print ('Hello World’)
print ("Sanjivani")
print('''College of Engineering''')
Output
Hello World
Sanjivani
College of Engineering

 Example 2:
name='Sonal’
rollno=10
print('Name is ',name)
print('Roll no is ',rollno)
Output
Name is Sonal
Roll no is 10
Example 3:
name='Sonal’
rollno=10
print('Name is ',name, 'Roll no is
',rollno)
Output
Name is Sonal Roll no is 10

 Example 4:
name='Sonal’
rollno=10
print(f'Name is {name}. Roll no is {rollno}.')
Output
Name is Sonal. Roll no is 10.

 Syntax of print()
print(object(s), sep=separator, end=end, file=file, flush=flush)
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

 sep parameter: is used to specify the separator between the strings.
 Example:
name='Sonal’
rollno=10
print(f'Name is {name}',f' Roll no is {rollno}',sep='.')
Output
Name is Sonal. Roll no is 10

 end parameter: . Specify what to print at the end.
 Example:
name='Sonal’
rollno=10
print(f'Name is {name}.',end=' ‘)
print(f' Roll no is {rollno}.')
Output
Name is Sonal. Roll no is 10.

 Python input() function is used to take user input.
 By default, it returns the user input in form of a string.
 Syntax:
input('prompt message’)
 Example:
name=input('Enter your name’)
print(f'Name is {name}.’)
print(type(name))
Output
Enter your nameSonal
Name is Sonal.<class 'str'>

 Example:
name=input('Enter your name’)
print(f'Name is {name}.’)
print(type(name))
rollno=int(input('Enter roll no’))
#int() use to convert string to integer value
print(f'Roll no is {rollno}.’)
print(type(rollno))
Output
Enter your nameSonal
Name is Sonal.
<class 'str’>
Enter roll no10
Roll no is 10.
<class 'int'>

 Operators:Operators are symbol used to perform operations on
variables and values.
 Operands:
The values or variables that an operator acts on are called
operands.
 A sequence of operands and operators is called expression.
Example: a+b-5
A + B - 5
Operands
Operator

1. Arithmetic operators
2. Assignment operators
3. Comparison operators
4. Logical operators
5. Identity operators
6. Membership operators
7. Bitwise operators

1. Arithmetic operators are used with numeric values to perform
common mathematical operations:
2. Assume x=10, y=5
Operator Name Example Output
+ Addition print(x+y) 15
- Subtraction print(x-y) 5
* Multiplication print(x*y) 50
/ Division print(x/y) 2.0
% Modulus print(x%y) 0
** Exponentiation print(x**y) 100000
// Floor Division x//y 2

a=10
b=20
c=a+b
print(“Addition is ”,c)
c=a-b
print(“Subtraction is ”,c)
c=a*b
print(“Multiplication is ”,c)
c=a/b
print(“Division is ”,c)
Output:
Addition is 30
Subtraction is -10
Multiplication is 200
Division is 0.5

 Assignment operators are used to assign values to variables:
Operator Description
= Assign value of right side of expression to left side operand
+= Add and Assign: Add right side operand with left side operand and then assign to left operand
-= Subtract AND: Subtract right operand from left operand and then assign to left operand: True if both operands
are equal
*= Multiply AND: Multiply right operand with left operand and then assign to left operand
/= Divide AND: Divide left operand with right operand and then assign to left operand
%= Modulus AND: Takes modulus using left and right operands and assign result to left operand
//= Divide(floor) AND: Divide left operand with right operand and then assign the value(floor) to left operand
**= Exponent AND: Calculate exponent(raise power) value using operands and assign value to left operand

a=10
b=20
print("a is ",a)
print("b is ",b)
a += 1
print("Add 1 to a ",a)
b -= 1
print("Subtract 1 from b ",b)
a **= 2
print("a square is ", a)
Output:
a is 10
b is 20
Add 1 to a 11
Subtract 1 from b 19
a square is 121

 Comparison operators are used to compare two values:
Operator Name Example
== Equal a==b
!= Not Equal a!=b
> Greater than a>b
< Less than a<b
>= Greater than or equal to a>=b
<= Less than or equal to a<=b

x=10
y=20
print(x==y)
print(x!=y)
print(x<y)
print(x>y)
print(x<=y)
print(x>=y)
Output:
False
True
True
False
True
False

 Logical operators are used to combine conditional statements:
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)

x=10
y=20
print(x==y and x<y)
print(x!=y or x>y)
print(not(x<y))
Output:
False
True
False

 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:
is Returns true if both
variables are the same object
a is y
is not Returns true if both
variables are not the same
object
a is not y

x=10
y=10
print(x is y)
print(x is not y)
Output:
True
False

 Membership operators are used to test if a sequence is presented in an
object:
in Returns True if a sequence with the
specified value is present in the
object
a in b
not in Returns True if a sequence with the
specified value is not present in the
object
a not in b

x='sanjivani’
print('s' in x)
print('s' not in x)
print('S' in x)
print('S' not in x)
y='anji’
print(y in x)
print(x in y)
Output:
True
False
False
True
True
False

 In Python, bitwise operators are used to performing bitwise calculations on integers.
 The integers are first converted into binary and then operations are performed on bit
by bit, hence the name bitwise operators.
 Then the result is returned in decimal format.
OPERATOR DESCRIPTION SYNTAX
& Bitwise AND x & y
| Bitwise OR x | y
~ Bitwise NOT ~x
^ Bitwise XOR x ^ y
>> Bitwise right shift x>>
<< Bitwise left shift x<<

 Bitwise AND operator Returns 1 if both the bits are 1 else 0.
 Example:
a=10= 1010 (Binary)
b=4=0100 (Binary)
a&b = 1010
&
0100
=0000(Binary)
=0 (Decimal)

 Bitwise or operator Returns 1 if either of the bit is 1 else 0.
 Example:
a=10= 1010 (Binary)
b=4=0100 (Binary)
A|b = 1010
|
0100
=1110(Binary)
=14 (Decimal)

 Bitwise not operator: Returns one’s complement of the number.
 Example:
a=10=1010 (Binary)
~a=~1010
=~(1010)
= (0101)
= 5 (Decimal)

 Bitwise xor operator: Returns 1 if one of the bits is 1 and the other is 0 else
returns false.
 Example:
a=10= 1010 (Binary)
b=4=0100 (Binary)
a^b = 1010
^
0100
=1110(Binary)
=14 (Decimal)

a = 10
b = 4
print("a & b =", a & b)
print("a | b =", a | b)
print("a ^ b =", a ^ b)
Output:
a & b = 0
a | b = 14
a ^ b = 14

 Bitwise right shift: Shifts the bits of the number to the right and fills 0 on voids
left( fills 1 in the case of a negative number) as a result.
 Similar effect as of dividing the number with some power of two.
 Example:
a=10= 0000 1010 (Binary)
a>>1=0000 0101 = 5
Example 2:
a= -10 = 1111 0110
a>>1 = 1111 1011 = -5

 Bitwise left shift: Shifts the bits of the number to the left and fills 0 on voids right
as a result.
 Similar effect as of multiplying the number with some power of two.
 Example:
a=10= 0000 1010 (Binary)
A<<1= 0001 0100 = 20
Example 2:
a= -10 = 1111 0110
A<<1 = 1110 1100 = -20

a = 10
b = -10
print("a >> 1 =", a >> 1)
print("b >> 1 =", b >> 1)
a = 5
b = -10
print("a << 1 =", a << 1)
print("b << 1 =", b << 1)
Output:
a >> 1 = 5
b >> 1 = -5
a << 1 = 10
b << 1 = -20

 A statement is an instruction that the Python interpreter can
execute.
 Python statement ends with the token NEWLINE character. It
means each line in a Python script is a statement.
 There are mainly four types of statements in Python,
 print statements: print(“hello”)
 Assignment statements: a=100
 Conditional statements: if (a>10):
Print(“a is greater than 10”)
 Looping statements.: for x in range(6):
print(x)

Python statement ends with the token NEWLINE character.
But we can extend the statement over multiple lines using line
continuation character ().
This is known as an explicit continuation.
add=20+30+
50+60+
90
print(add)
Output: 250

We can use parentheses () to write a multi-line statement.
We can add a line continuation statement inside it.
Whatever we add inside a parentheses () will treat as a single
statement even it is placed on multiple lines.
addition = (10 + 20 +
30 + 40 +
50 + 60 + 70)
print(addition)
# Output: 280

 Compound statement contain (groups of) other statements; they affect or control the
execution of those other statements in some way.
 The compound statement includes the conditional and loop statement.
 if statement: t is a control flow statement that will execute statements under it if
the condition is true. Also known as a conditional statement.
 while statement: The while loop statement repeatedly executes a code block while a
particular condition is true. Also known as a looping statement.
 for statement: Using for loop statement, we can iterate any sequence or iterable
variable. The sequence can be string, list, dictionary, set, or tuple. Also known as a
looping statement.
 try statement: specifies exception handlers.
 with statement: Used to cleanup code for a group of statements, while the with
statement allows the execution of initialization and finalization code around a
block of code.

 Python has various simple statements for a specific purpose.
1. Expression Statement
2. The pass statement
3. The del statement
4. The return statement
5. The import statement
6. The continue and break statement

 A combination of operands and operators is called an expression.
 The expression in Python produces some value or result after being
interpreted by the Python interpreter.
 Example:
r = a+b
res =10+a
result = 20+30
 An expression in Python can contain identifiers, operators, and operands.
 An identifier is a name that is used to define and identify a class, variable,
or function in Python.

1.Constant Expressions
2.Arithmetic Expressions
3.Integral Expressions
4.Floating Expressions
5.Relational Expressions
6.Logical Expressions
7.Combinational Expression

 A constant expression in Python that contains only constant values
is known as a constant expression.
 In a constant expression in Python, the operator(s) is a constant.
 A constant is a value that cannot be changed after its initialization.
 Example:
a = 20 +10

 An expression in Python that contains a combination of arithmetic
operators, operands, and sometimes parenthesis is known as
an arithmetic expression.
 The result of an arithmetic expression is also a numeric value
 Example:
x = c+d
x = c * a

 An integral expression in Python is used for computations and type
conversion (integer to float, a string to integer, etc.).
 An integral expression always produces an integer value as a
resultant.
 Example:
a = 5
b = 5.0
res = a + int(b)

 A floating expression in Python is used for computations and type
conversion (integer to float, a string to integer, etc.).
 A floating expression always produces a floating-point number as a
resultant.
 Example:
a = 5
b = 5.0
res = float(a) + b

 A relational expression in Python can be considered as a
combination of two or more arithmetic expressions joined using
relational operators.
 The overall expression results in either True or False (boolean
result).
 We have four types of relational operators in Python (i.e. > , < , >= ,
<=)(i.e.>,<,>=,<=).
 A relational operator produces a boolean result so they are also
known as Boolean Expressions.
 Example:
10+15>20

 As the name suggests, a logical expression performs the logical
computation using logical operators, and the overall expression
results in either True or False (boolean result).
 Example:
a and b
a or b
a not b
a=3
b=3
if a>0 and b>0:
print(“a and b greater than zero”)

 As the name suggests, a combination expression can contain a single
or multiple expressions which result in an integer or boolean value
depending upon the expressions involved.
 Example:
x = 5
y = 5
res = x + (2 *6)

 A boolean expression is an expression that is either true or false.
 Example:
5 > 3
True
5 >9
False

Python defines type conversion functions to directly
convert one data type to another which is useful in day-to-
day and competitive programming.
There are two types of Type Conversion in Python:
 Implicit Type Conversion
 Explicit Type Conversion

 In Implicit type conversion of data types in Python, the Python
interpreter automatically converts one data type to another without
any user involvement.
Program Output
x = 10
print("x is of type:",type(x))
y = 10.6
print("y is of type:",type(y))
z = x + y
print(z)
print("z is of type:",type(z))
x is of type: <class 'int'>
y is of type: <class 'float'>
20.6
z is of type: <class 'float'>

1.int(a, base): This function
converts any data type to integer.
‘Base’ specifies the base in which
string is if the data type is a string.
2.float(): This function is used to
convert any data type to a floating-
point number.
3.tuple() : This function is used
to convert to a tuple.
4.set() : This function returns the type
after converting to set.
5.list() : This function is used to
convert any data type to a list type.
6.dict() : This function is used
to convert a tuple of order (key,value)
into a dictionary.
7.str() : Used to convert integer into a
string.
8.complex(real,imag) : This
function converts real numbers to
complex(real,imag) number.
In Explicit Type Conversion in Python, the data type is manually
changed by the user as per their requirement.
Various forms of explicit type conversion are explained below:

x=5
print("x is of type:",type(x))
y=float(x)
print("y is of type:",type(y))
z=str(x)
print("z is of type:",type(z))
Output:
x is of type: <class 'int’>
y is of type: <class ‘float’>
z is of type: <class ‘str'>

Solve this :
3 + 4 x 2 – 1
3 + 4 / 2 – 1
 BIDMAS
 BIDMAS, which stands
for Brackets, Indices, Division, Multiplication, Addition
and Subtraction.

 The operator precedence in Python is listed in the following table. It is
in descending order (upper group has higher precedence than the lower
ones).
Priority Operator Meaning
1 () Parentheses
2 ** Exponent
3 +,-,~ Unary plus, Unary Minus, Bitwise NOT
4 *,/,//,% Multiplication, Division, Floor division,
Modulus
5 +,- Addition, Subtraction
6 <<,>> Bitwise shift operators
7 & Bitwise AND
8 ^ Bitwise XOR
9 | Bitwise OR
10 ==, !=, >, >=, <, <=, is, is not, in, not
in
Comparisons, Identity, Membership operators
11 not Logical NOT
12 and Logical AND
13 or Logical OR

ESIT135 : Unit 1 Python Basics Concepts

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