This document provides an overview of the Python programming language. It outlines the topics that will be covered in a course on Python programming, including an introduction to Python, installing Python, data types, variables, strings, lists, tuples, sets, dictionaries, and functions. It also provides details on Python's history and design philosophy, and explains why Python is a popular language for tasks like data analysis, machine learning, and web development.

1. School Of Computing Science & Engineering
Programming with Python
Overview of Python
Programming
Galgotias University, Greater Noida

2.  Looping
Outline
 Introduction to python
 Installing python
 Hello World program using python
 Data types
 Variables
 Expressions
 Functions
 String
 List
 Tuple
 Set
 Dictionary
 Functions

3.  Unit 01 – Overview of Python 3
Introduction to Python
• Python is an open source, interpreted, high-level, general-purpose programming
language.
• Python's design philosophy emphasizes code readability with its notable use of
significant whitespace.
• Python is dynamically typed and garbage-collected language.
• Python was conceived in the late 1980s as a successor to the ABC language.
• Python was Created by Guido van Rossum and first released in 1991.
• Python 2.0, released in 2000,
• introduced features like list comprehensions and a garbage collection system with
reference counting.
• Python 3.0 released in 2008 and current version of python is 3.8.3 (as of June-
2020).
• The Python 2 language was officially discontinued in 2020

4.  Unit 01 – Overview of Python 4
Why Python?
• Python has many advantages
• Easy to learn
• Less code
• Syntax is easier to read
• Open source
• Huge amount of additional open-source libraries
Some libraries listed below.
• matplotib for plotting charts and graphs
• BeautifulSoup for HTML parsing and XML
• NumPy for scientific computing
• pandas for performing data analysis
• SciPy for engineering applications, science, and mathematics
• Scikit for machine learning
• Django for server-side web development
• And many more..

5.  Unit 01 – Overview of Python 5
Installing Python
• For Windows & Mac:
• To install python in windows you need to download installable file from
https://www.python.org/downloads/
• After downloading the installable file you need to execute the file.
• For Linux :
• For ubuntu 16.10 or newer
• sudo apt-get update
• sudo apt-get install python3.8
• To verify the installation
• Windows :
• python --version
• Linux :
• python3 --version (linux might have python2 already installed, you can check python 2 using python --version)
• Alternatively we can use anaconda distribution for the python installation
• http://anaconda.com/downloads
• Anaconda comes with many useful inbuilt libraries.

6.  Unit 01 – Overview of Python 6
Hello World using Python
• To write python programs, we can use any text editors or IDE (Integrated
Development Environment), Initially we are going to use Visual Studio Code.
• Create new file in editor, save it as first.py (Extensions for python programs will
be .py)
• To run the python file open command prompt and change directory to where your
python file is
• Next, run python command (python filename.py)
print("Hello World from python")
1
first.py Python line does not end with ;

7.  Unit 01 – Overview of Python 7
Data types in Python
Name Type Description
Data Types
Integer Int Whole number such as 0,1,5, -5 etc..
Float Float Numbers with decimal points such as 1.5, 7.9, -8.2 etc..
String Str Sequence of character (Ordered) such as “Galgotias”, ‘University’, “Greater Noida” etc..
Boolean Bool Logical values indicating True or False (T and F here are capital in python)
Data Structures
List list
Ordered Sequence of objects, will be represented with square brackets [ ]
Example : [ 18, “galgotias”, True, 102.3 ]
Tuple tup
Ordered immutable sequence of objects, will be represented with round brackets ( )
Example : ( 18, “galgotias”, True, 102.3 )
Set set
Unordered collection of unique objects, will be represented with the curly brackets { }
Example : { 18, “galgotias”, True, 102.3 }
Dictionary dict
Unordered key : value pair of objects , will be represented with curly brackets { }
Example : { “college”: “galgotias”, “course”: “MCA” }

8.  Unit 01 – Overview of Python 8

9.  Unit 01 – Overview of Python 9
Variables in Python
• A Python variable is a reserved memory location to store values.
• Unlike other programming languages, Python has no command for declaring a variable.
• A variable is created the moment you first assign a value to it.
• Python uses Dynamic Typing so,
• We need not to specify the data types to the variable as it will internally assign the data type to the
variable according to the value assigned.
• we can also reassign the different data type to the same variable, variable data type will change to
new data type automatically.
• We can check the current data type of the variable with type(variablename) in-built function.
• Rules for variable name
• Name can not start with digit
• Space not allowed
• Can not contain special character
• Python keywords not allowed
• Should be in lower case

10.  Unit 01 – Overview of Python 10
Example of Python variable
• Example :
x = 10
print(x)
print(type(x))
y = 123.456
print(y)
x = “Galgotias University"
print(x)
print(type(x))
1
2
3
4
5
6
7
8
9
10
demo.py
python demo.py
1
Run in terminal
10
int
123.456
Galgotias University
str
1
2
3
4
5
Output
Reassign same variable to hold different data type

11.  Unit 01 – Overview of Python 11
String in python
• String is Ordered Sequence of character such as “Galgotias”, ‘University’, “Greater
Noida” etc..
• Strings are arrays of bytes representing Unicode characters.
• String can be represented as single, double or triple quotes.
• String with triple Quotes allows multiple lines.
• String in python is immutable.
• Square brackets can be used to access elements of the string, Ex. “Galgotia”[1] =
a, characters can also be accessed with reverse index like “Galgotia”[-1] = a.
x = " G a l g o t i a "
index = 0 1 2 3 4 5 6 7
Reverse index = -8 -7 -6 -5 -4 -3 -2 -1
String index

12.  Unit 01 – Overview of Python 12
String functions in python
• Python has lots of built-in methods that you can use on strings, we are going to
cover some frequently used methods for string like
• len()
• count()
• capitalize(), lower(), upper()
• istitle(), islower(), isupper()
• find(), rfind(), replace()
• index(), rindex()
• Methods for validations like
• isalpha(), isalnum(), isdecimal(), isdigit()
• strip(), lstrip(), rstrip()
• Etc..
• Note : len() is not the method of the string but can be used to get the length of the
string
x = “Galgotia"
print(len(x))
1
2
lendemo.py
Output : 8 (length of “Galgotia”)

13.  Unit 01 – Overview of Python 13
String methods (cont.)
• count() method will returns the number of times a specified value occurs in a
string.
 title(), lower(), upper() will returns capitalized, lower case and upper case string respectively.
x = “Galgotias"
ca = x.count('a')
print(ca)
1
2
3
countdemo.py
Output : 2 (occurrence of ‘a’ in “Galgotias”)
x = “Galgotias University,Greater Noida"
c = x.title()
l = x.lower()
u = x.upper()
print(c)
print(l)
print(u)
1
2
3
4
5
6
7
changecase.py
Output : Galgitias University, Greater Noida
Output : galgotias university, greater noida
Output : GALGOTIAS UNIVERSITY, GREATER NOIDA

14.  Unit 01 – Overview of Python 14
String methods (cont.)
 istitle(), islower(), isupper() will returns True if the given string is capitalized, lower case and
upper case respectively.
 strip() method will remove whitespaces from both side of the string and returns the string.
 rstrip() and lstrip() will remove whitespaces from right and left side respectively.
x = ' Galgotias '
f = x.strip()
print(f)
1
2
3
stripdemo.py
Output : Galgotias (without space)
x = ’galgotias university'
c = x.istitle()
l = x.islower()
u = x.isupper()
print(c)
print(l)
print(u)
1
2
3
4
5
6
7
checkcase.py
Output : False
Output : True
Output : False

15.  Unit 01 – Overview of Python 15
String methods (cont.)
• find() method will search the string and returns the index at which they find the
specified value
• rfind() will search the string and returns the last index at which they find the
specified value
 Note : find() and rfind() will return -1 if they are unable to find the given string.
 replace() will replace str1 with str2 from our string and return the updated string
x = ’galgotia institute,noida, india'
f = x.find('in')
print(f)
1
2
3
finddemo.py
Output : 9 (occurrence of ‘in’ in x)
x = ’galgotia institute,noida,india'
r = x.rfind('in')
print(r)
1
2
3
rfinddemo.py
Output : 26 (last occurrence of ‘in’ in x)
x = ’galgotia institute, noida, india'
r = x.replace('india','INDIA')
print(r)
1
2
3
replacedemo.py
Output :
“galgotia institute, noida, INDIA”

16.  Unit 01 – Overview of Python 16
String methods (cont.)
• index() method will search the string and returns the index at which they find the
specified value, but if they are unable to find the string it will raise an exception.
• rindex() will search the string and returns the last index at which they find the
specified value , but if they are unable to find the string it will raise an exception.
• Note : find() and index() are almost same, the only difference is if find() is unable
to find the string it will return -1 and if index() is unable to find the string it will
raise an exception.
x = ’galgotia institute, noida, india'
f = x.index('in')
print(f)
1
2
3
indexdemo.py
Output : 9 (occurrence of ‘in’ in x)
x = ’galgotia institute,noida, india'
r = x.rindex('in')
print(r)
1
2
3
rindexdemo.py
Output : 27 (last occurrence of ‘in’ in x)

17.  Unit 01 – Overview of Python 17
String methods (cont.)
• isalnum() method will return true if all the characters in the string are alphanumeric (i.e
either alphabets or numeric).
• isalpha() and isnumeric() will return true if all the characters in the string are only
alphabets and numeric respectively.
• isdecimal() will return true is all the characters in the string are decimal.
• Note : isnuberic() and isdigit() are almost same, you suppose to find the difference as
Home work assignment for the string methods.
x = ’galgotia123'
f = x.isalnum()
print(f)
1
2
3
isalnumdemo.py
Output : True
x = '123.5'
r = x.isdecimal()
print(r)
1
2
3
isdecimaldemo.py
Output : True

18.  Unit 01 – Overview of Python 18
String Slicing
• We can get the substring in python using string slicing, we can specify start index,
end index and steps (colon separated) to slice the string.
x = ’galgotia institute of engineering and technology, noida, up, INDIA'
subx = x[startindex:endindex:steps]
syntax
x = ’galgotia institute of engineering and technology, noida, up, INDIA'
subx1 = x[0:8]
subx2 = x[49:54]
subx3 = x[62:]
subx4 = x[::2]
subx5 = x[::-1]
print(subx1)
print(subx2)
print(subx3)
print(subx4)
print(subx5)
1
2
3
4
5
6
7
8
9
10
11
strslicedemo.py
Output : galgotia
endindex will not be included in the substring
Output : noida
Output : INDIA
Output : gloi nttt fegneigadtcnlg,nia p NI
Output : AIDNI ,pu ,adion ,ygolonhcet dna gnireenigne fo etutitsni aitoglag

19.  Unit 01 – Overview of Python 19
String print format
• str.format() is one of the string formatting methods in Python3, which allows
multiple substitutions and value formatting.
• This method lets us concatenate elements within a string through positional
formatting.
• We can specify multiple parameters to the function
x = '{} institute, noida'
y = x.format(‘galgotia')
print(y)
print(x.format('ABCD'))
1
2
3
4
strformat.py
Output : galgotia institute, noida
Inline function call
Output : ABCD institute, noida
x = '{} institute, {}'
y = x.format(‘galgotia’,’India')
print(y)
print(x.format('ABCD','XYZ'))
1
2
3
4
strformat.py
Output : galgotia institute, india
Inline function call
Output : ABCD institute, XYZ

20.  Unit 01 – Overview of Python 20
String print format (cont.)
• We can specify the order of parameters in the string
• We can also specify alias within the string to specify the order
• We can format the decimal values using format method
x = '{1} institute, {0}'
y = x.format(‘galgotia’,’india')
print(y)
print(x.format('ABCD','XYZ'))
1
2
3
4
strformat.py
Output : india institute, galgotia
Inline function call
Output : XYZ institute, ABCD
x = '{collegename} institute, {cityname}'
print(x.format(collegename=‘abcd',cityname=‘xyz'))
1
2
strformat.py
Output : abcd institute, xyz
per = (438 / 500) * 100
x = 'result = {r:3.2f} %'.format(r=per)
print(x)
1
2
3
strformat.py
Output : result = 87.60 %
width precision

21.  Unit 01 – Overview of Python 21
Data structures in python
• There are four built-in data structures in Python - list, dictionary, tuple and set.
• Lets explore all the data structures in detail…
Name Type Description
List list
Ordered Sequence of objects, will be represented with square brackets [ ]
Example : [ 18, “abcd”, True, 102.3 ]
Dictionary dict
Unordered key : value pair of objects , will be represented with curly brackets { }
Example : { “college”: “abcd”, “code”: “054” }
Tuple tup
Ordered immutable sequence of objects, will be represented with round brackets ( )
Example : ( 18, “abcd”, True, 102.3 )
Set set
Unordered collection of unique objects, will be represented with the curly brackets { }
Example : { 18, “abcd”, True, 102.3 }

22.  Unit 01 – Overview of Python 22
List
• List is a mutable ordered sequence of objects, duplicate values are allowed inside
list.
• List will be represented by square brackets [ ].
• Python does not have array, List can be used similar to Array.
• We can use slicing similar to string in order to get the sub list from the list.
my_list = [‘abcdefg’, ’institute', ’nida']
print(my_list[1])
print(len(my_list))
my_list[2] = ”noida"
print(my_list)
print(my_list[-1])
1
2
3
4
5
6
list.py
Output : 3 (length of the List)
Output : institute (List index starts with 0)
Output : [‘abcdefg', 'institute', ‘noida']
Note : spelling of noida is updated
my_list = [‘galgotia', 'institute’, ’noida’,’up','INDIA']
print(my_list[1:3])
1
2
list.py
Output : ['institute', ‘noida]
Note : end index not included
Output : Noida (-1 represent last element)

23.  Unit 01 – Overview of Python 23
List methods
• append() method will add element at the end of the list.
• insert() method will add element at the specified index in the list
• extend() method will add one data structure (List or any) to current List
my_list = [‘galgotia', 'institute', ’noida']
my_list.append(‘up')
print(my_list)
1
2
3
appendlistdemo.py
Output : [‘galgotia', 'institute', ‘noida', ‘up']
my_list = [galgotia', 'institute', ’noida ']
my_list.insert(2,'of')
my_list.insert(3,'engineering')
print(my_list)
1
2
3
4
insertlistdemo.py
Output : [‘galgotia', 'institute', 'of', 'engineering', ‘noida']
my_list1 = [‘galgotia', 'institute']
my_list2 = [‘noida’,’up']
my_list1.extend(my_list2)
print(my_list1)
1
2
3
4
extendlistdemo.py
Output : [‘galgotia', 'institute’, ‘noida’, ‘up']

24.  Unit 01 – Overview of Python 24
List methods (cont.)
• pop() method will remove the last element from the list and return it.
• remove() method will remove first occurrence of specified element
• clear() method will remove all the elements from the List
• index() method will return first index of the specified element.
my_list = [‘galgotia', 'institute', ’noida ']
temp = my_list.pop()
print(temp)
print(my_list)
1
2
3
4
poplistdemo.py
Output : noida
my_list = [‘galgotia', 'institute’,’galgotia ’noida ']
my_list.remove(‘galgotia')
print(my_list)
1
2
3
removelistdemo.py
Output : ['institute', ‘galgotia', ‘noida']
my_list = [‘galgotia', 'institute’,’galgotia ’noida ']
my_list.clear()
print(my_list)
1
2
3
clearlistdemo.py
Output : []
Output : [‘galgotia', 'institute‘]

25.  Unit 01 – Overview of Python 25
List methods (cont.)
• count() method will return the number of occurrence of the specified element.
• reverse() method will reverse the elements of the List
• sort() method will sort the elements in the List
my_list = [‘abc', 'institute', ’abc’,’xyz]
c = my_list.count(‘abc')
print(c)
1
2
3
countlistdemo.py
Output : 2
my_list = [‘abc', 'institute’,’xyz']
my_list.reverse()
print(my_list)
1
2
3
reverselistdemo.py
Output : [‘xyz', ‘institute’,’abc']
my_list = [galgotia', 'institute’,’galgotia ’noida ']
my_list.sort()
print(my_list)
my_list.sort(reverse=True)
print(my_list)
1
2
3
4
5
sortlistdemo.py
Output : [‘galgotia', ‘galgotia', ‘institute', ‘noida']
Output : [‘Noida’, 'institute’,galgotia’,
galgotia ']

26.  Unit 01 – Overview of Python 26
Tuple
• Tuple is a immutable ordered sequence of objects, duplicate values are allowed
inside list.
• Tuple will be represented by round brackets ( ).
• Tuple is similar to List but List is mutable whearas Tuple is immutable.
my_tuple = (‘abcd','institute','of','engineering',’noida')
print(my_tuple)
print(my_tuple.index('engineering'))
print(my_tuple.count('of'))
print(my_tuple[-1])
1
2
3
4
5
tupledemo.py
Output : 3 (index of ‘engineering’)
Output : (‘abc', 'institute', 'of', 'engineering', '‘noida’)
Output : 2
Output : noida

27.  Unit 01 – Overview of Python 27
Dictionary
• Dictionary is a unordered collection of key value pairs.
• Dictionary will be represented by curly brackets { }.
• Dictionary is mutable.
my_dict = {'college’: ‘abcd’, 'city’: ‘Noida’, 'type':"engineering"}
print(my_dict['college'])
print(my_dict.get('city'))
1
2
3
dictdemo.py
values can be accessed using key inside square brackets
as well as using get() method
Output : abcd
noida
my_dict = { 'key1':'value1', 'key2':'value2' }
syntax
Key value is seperated by : Key value pairs is seperated by ,

28.  Unit 01 – Overview of Python 28
Dictionary methods
• keys() method will return list of all the keys associated with the Dictionary.
• values() method will return list of all the values associated with the Dictionary.
• items() method will return list of tuples for each key value pair associated with the
Dictionary.
my_dict = {'college’: ‘abcd’, 'city’: ‘indore’,'type’: ‘engineering’}
print(my_dict.keys())
1
2
keydemo.py
my_dict = {'college’: ‘abcd’, 'city’: ‘indore’,'type’: ‘engineering’}
print(my_dict.values())
1
2
valuedemo.py
Output : [‘abcd', ‘indore', 'engineering']
my_dict = {'college’: ‘abcd’, 'city’: ‘indore’,'type’: ‘engineering’}
print(my_dict.items())
1
2
itemsdemo.py
Output : [('college', ‘abcd'), ('city', ‘indore), ('type',
'engineering')]
Output : ['college', 'city', 'type']

29.  Unit 01 – Overview of Python 29
Set
• Set is a unordered collection of unique objects.
• Set will be represented by curly brackets { }.
• Set has many in-built methods such as add(), clear(), copy(), pop(), remove() etc..
which are similar to methods we have previously seen.
• Only difference between Set and List is that Set will have only unique elements
and List can have duplicate elements.
my_set = {1,1,1,2,2,5,3,9}
print(my_set)
1
2
tupledemo.py
Output : {1, 2, 3, 5, 9}

30.  Unit 01 – Overview of Python 30
Operators in python
• We can segregate python operators in the following groups
• Arithmetic operators
• Assignment operators
• Comparison operators
• Logical operators
• Identity operators
• Membership operators
• Bitwise operators
• We will discuss some of the operators from the given list in detail in some of next
slides.

31.  Unit 01 – Overview of Python 31
Arithmetic Operators
• Note : consider A = 10 and B = 3
Operator Description Example Output
+ Addition A + B 13
- Subtraction A - B 7
/ Division A / B 3.3333333333333335
* Multiplication A * B 30
% Modulus return the remainder A % B 1
// Floor division returns the quotient A // B 3
** Exponentiation A ** B 10 * 10 * 10 = 1000

32.  Unit 01 – Overview of Python 32
Examples
a = 7
b = 2
# addition
print ('Sum: ', a + b)
# subtraction
print ('Subtraction: ', a - b)
# multiplication
print ('Multiplication: ', a * b)
# division
print ('Division: ', a / b)
# floor division
print ('Floor Division: ', a // b)
# modulo
print ('Modulo: ', a % b)
# a to the power b
print ('Power: ', a ** b)
Sum: 9
Subtraction: 5
Multiplication: 14
Division: 3.5
Floor Division: 3
Modulo: 1
Power: 49

33.  Unit 01 – Overview of Python 33
Assignment Operator are used to assign values to variables
Operator Name Example
= Assignment Operator a = 7
+= Addition Assignment a += 1 # a = a + 1
-=
Subtraction
Assignment
a -= 3 # a = a - 3
*=
Multiplication
Assignment
a *= 4 # a = a * 4
/= Division Assignment a /= 3 # a = a / 3
%=
Remainder
Assignment
a %= 10 # a = a % 10
**= Exponent Assignment a **= 10 # a = a ** 10

34.  Unit 01 – Overview of Python 34
Python Comparison Operators
Comparison operators compare two values/variables and return a boolean result: True or False.
Operator Meaning Example
== Is Equal To 3 == 5 gives us False
!= Not Equal To 3 != 5 gives us True
> Greater Than 3 > 5 gives us False
< Less Than 3 < 5 gives us True
>= Greater Than or Equal To 3 >= 5 give us False
<= Less Than or Equal To 3 <= 5 gives us True

35.  Unit 01 – Overview of Python 35
Examples
a = 5
b = 2
# equal to operator
print('a == b =', a == b)
# not equal to operator
print('a != b =', a != b)
# greater than operator
print('a > b =', a > b)
# less than operator
print('a < b =', a < b)
# greater than or equal to operator
print('a >= b =', a >= b)
# less than or equal to operator
print('a <= b =', a <= b)
a == b = False
a != b = True
a > b = True
a < b = False
a >= b = True
a <= b = False

36.  Unit 01 – Overview of Python 36
Logical Operators
• Note : consider A = 10 and B = 3
Operator Description Example Output
and Returns True if both statements are true A > 5 and B < 5 True
or Returns True if one of the statements is true A > 5 or B > 5 True
not
Negate the result, returns True if the result is
False
not ( A > 5 ) False
# logical AND
print(True and True) # True
print(True and False) # False
# logical OR
print(True or False) # True
# logical NOT
print(not True) # False

37.  Unit 01 – Overview of Python 37
Identity & Member Operators
• Identity Operator
• Note : consider A = [1,2], B = [1,2] and C=A
• x1 = 5
• y1 = 5
• x2 = 'Hello'
• y2 = 'Hello'
• x3 = [1,2,3]
• y3 = [1,2,3]
• print(x1 is not y1) # prints False
• print(x2 is y2) # prints True
• print(x3 is y3) # prints False
Operator Description Example Output
is
Returns True if both variables are
the same object
A is B
A is C
FALSE
TRUE
is not
Returns True if both variables are
different object
A is not B TRUE
x3 and y3 are lists. They are equal but not identical. It is because the
interpreter locates them separately in memory although they are equal.

38.  Unit 01 – Overview of Python 38
Operator Description Example Output
in
Returns True if a sequence with the
specified value is present in the object
A in B TRUE
not in
Returns True if a sequence with the
specified value is not present in the object
A not in B FALSE
Member Operator
Note : consider A = 2 and B = [1,2,3]
x = 'Hello world'
y = {1:'a', 2:'b'}
# check if 'H' is present in x string
print('H' in x) # prints True
# check if 'hello' is present in x string
print('hello' not in x) # prints True
# check if '1' key is present in y
print(1 in y) # prints True

39.  Unit 01 – Overview of Python 39
X is greater than 5
1
Output
If statement
• if statement is written using the if keyword followed by condition and colon(:) .
• Code to execute when the condition is true will be ideally written in the next line
with Indentation (white space).
• Python relies on indentation to define scope in the code (Other programming
languages often use curly-brackets for this purpose).
if some_condition :
# Code to execute when condition is true
1
2
Syntax if statement ends with :
Indentation (tab/whitespace) at the beginning
x = 10
if x > 5 :
print("X is greater than 5")
1
2
3
4
ifdemo.py
python ifdemo.py
1
Run in terminal

40.  Unit 01 – Overview of Python 40
X is less than 5
1
Output
If else statement
if some_condition :
# Code to execute when condition is true
else :
# Code to execute when condition is false
1
2
3
4
Syntax
x = 3
if x > 5 :
print("X is greater than 5")
else :
print("X is less than 5")
1
2
3
4
5
6
ifelsedemo.py
python ifelsedemo.py
1
Run in terminal

41.  Unit 01 – Overview of Python 41
X is greater than 5
1
Output
If, elif and else statement
if some_condition_1 :
# Code to execute when condition 1 is true
elif some_condition_2 :
# Code to execute when condition 2 is true
else :
# Code to execute when both conditions are false
1
2
3
4
5
6
Syntax
x = 10
if x > 12 :
print("X is greater than 12")
elif x > 5 :
print("X is greater than 5")
else :
print("X is less than 5")
1
2
3
4
5
6
7
8
ifelifdemo.py
python ifelifdemo.py
1
Run in terminal

42.  Unit 01 – Overview of Python 42
For loop in python
• Many objects in python are iterable, meaning we can iterate over every element in
the object.
• such as every elements from the List, every characters from the string etc..
• We can use for loop to execute block of code for each element of iterable object.
for temp_item in iterable_object :
# Code to execute for each object in iterable
1
2
Syntax For loop ends with :
Indentation (tab/whitespace) at the beginning
my_list = [1, 2, 3, 4]
for list_item in my_list :
print(list_item)
1
2
3
fordemo1.py Output :
1
2
3
4
my_list = [1,2,3,4,5,6,7,8,9]
for list_item in my_list :
if list_item % 2 == 0 :
print(list_item)
1
2
3
4
fordemo2.py Output :
2
4
6
8

43.  Unit 01 – Overview of Python 43
For loop (tuple unpacking)
• Sometimes we have nested data structure like List of tuples, and if we want to
iterate with such list we can use tuple unpacking.
• range() function will create a list from 0 till (not including) the value specified as
argument.
my_list = [(1,2,3), (4,5,6), (7,8,9)]
for list_item in my_list :
print(list_item[1])
1
2
3
withouttupleunapacking.py
Output :
2
5
8
my_list = [(1,2,3), (4,5,6), (7,8,9)]
for a,b,c in my_list :
print(b)
1
2
3
withtupleunpacking.py
Output :
2
5
8
This
technique is
known as
tuple
unpacking
my_list = range(5)
for list_item in my_list :
print(list_item)
1
2
3
rangedemo.py Output :
0
1
2
3
4

44.  Unit 01 – Overview of Python 44
While loop
• While loop will continue to execute block of code until some condition remains
True.
• For example,
• while felling hungry, keep eating
• while have internet pack available, keep watching videos
while some_condition :
# Code to execute in loop
1
2
Syntax while loop ends with :
Indentation (tab/whitespace) at the beginning
x = 0
while x < 3 :
print(x)
x += 1 # x++ is valid in python
1
2
3
4
whiledemo.py
Output :
0
1
2
x = 5
while x < 3 :
print(x)
x += 1 # x++ is valid in python
else :
print("X is greater than 3")
1
2
3
4
5
6
withelse.py
Output :
X is greater
than 3

45.  Unit 01 – Overview of Python 45
price = 50
quantity = 5
amount = price*quantity
if amount > 100:
if amount > 500:
print("Amount is greater than 500")
else:
if amount < 500 and amount > 400:
print("Amount is")
elif amount < 500 and amount > 300:
print("Amount is between 300 and 500")
else:
print("Amount is between 200 and 500")
elif amount == 100:
print("Amount is 100")
else:
print("Amount is less than 100")

46.  Unit 01 – Overview of Python 46
For Loop
numNames = { 1:'One', 2: 'Two', 3: 'Three’}
for k,v in numNames.items():
print("key = ", k , ", value =", v)

47.  Unit 01 – Overview of Python 47
break, continue & pass keywords
• break : Breaks out of the current
closest enclosing loop.
• continue : Goes to the top of the
current closest enclosing loop.
• Pass : Does nothing at all, will be used
as a placeholder in conditions where
you don’t want to write anything.
for temp in range(5) :
if temp == 2 :
break
print(temp)
1
2
3
4
5
breakdemo.py
Output :
0
1
for temp in range(5) :
if temp == 2 :
continue
print(temp)
1
2
3
4
5
continuedemo.py Output :
0
1
3
4
for temp in range(5) :
pass
1
2
passdemo.py
Output : (nothing)

48.  Unit 01 – Overview of Python 48
Functions in python
• Creating clean repeatable code is a key part of becoming an effective
programmer.
• A function is a block of code which only runs when it is called.
• In Python a function is defined using the def keyword:
def function_name() :
#code to execute when function is called
Syntax ends with :
Indentation (tab/whitespace) at the beginning
def seperator() :
print('==============================')
print("hello world")
seperator()
print("from abcd college")
seperator()
print(”noida")
1
2
3
4
5
6
7
8
functiondemo.py
Output :
hello world
==============================
from abcd college
==============================
noida

49.  Unit 01 – Overview of Python 49
Function (cont.) (DOCSTRIGN & return)
• Doc string helps us to define the documentation about the function within the
function itself.
• return statement : return allows us to assign the output of the function to a new
variable, return is use to send back the result of the function, instead of just
printing it out.
def function_name() :
'''
DOCSTRING: explains the function
INPUT: explains input
OUTPUT: explains output
'''
#code to execute when function is called
Syntax Enclosed within triple quotes
def add_number(n1,n2) :
return n1 + n2
sum1 = add_number(5,3)
sum2 = add_number(6,1)
print(sum1)
print(sum2)
1
2
3
4
5
6
7
whiledemo.py
Output :
8
7

50.  Unit 01 – Overview of Python 50
# function with two arguments
def add_numbers(num1, num2):
sum = num1 + num2
print("Sum: ",sum)
# function call with two values
add_numbers(5, 4)
# Output: Sum: 9
Function return Type
# function definition
def find_square(num):
result = num * num
return result
# function call
square = find_square(3)
print('Square:',square)
# Output: Square: 9
# function that adds two numbers
def add_numbers(num1, num2):
sum = num1 + num2
return sum
# calling function with two values
result = add_numbers(5, 4)
print('Sum: ', result)
# Output: Sum: 9

51. print("Hello World")
How to print “Hello + Username” with the user’s name on Python?
usertext = input("What is your name? ")
print("Hello", usertext)
?

52. num1 = float(input('Enter first number: '))
num2 = float(input('Enter second number: '))
num3 = float(input('Enter third number: '))
avg = (num1 + num2 + num3)/3
print('The average of numbers = %0.2f' %avg)

53. principal = float(input('Enter amount: ‘))
time = float(input('Enter time: ‘))
rate = float(input('Enter rate: ‘))
simple_interest = (principal*time*rate)/100
compound_interest = principal * ( (1+rate/100)**time - 1)
print('Simple interest is: %f' % (simple_interest))
print('Compound interest is: %f' %(compound_interest))

54. celsius_1 = float(input("Temperature value in degree Celsius: " ))
Fahrenheit_1 = (celsius_1 * 1.8) + 32
print('The %.2f degree Celsius is equal to: %.2f Fahrenheit'%(celsius_1, Fahrenheit_1))

56. num = int(input("Enter a number: "))
factorial = 1
if num < 0:
print(" Factorial does not exist for negative numbers")
elif num == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,num + 1):
factorial = factorial*i
print("The factorial of",num,"is",factorial)

57. num = int(input("Enter a number: "))
if (num % 2) == 0:
print("{0} is Even number".format(num))
else:
print("{0} is Odd number".format(num))