Introduction to Python.pdf

Scope and
Application
02
Python
real-world
applications
and their scope
Installation
03
Understanding
the process of
installation of
python
Python Basics
04
Understanding
the basics of
python
Python:
Introduction
and Different
Versions
01
An introduction to
python programming
language, its versions,
and their comparative
study
Agenda

Python:
Introduction and
Different Versions
of Python

Python is a programming
language that was created by
Guido van Rossum
It was ﬁrst released in 1991
Features of python
programming language
Easy to learn, easy to code
Object oriented elements
Platform independent
Interpreted
Python: Introduction

There are two major versions of python, python 2.0, and python 3.0.
• Python 2.0 was released in the year 2000.
• Python 3.0 was released in the year 2008.
• Python 3.0 is the latest major release of python, and we will be using this version to write codes.
Python: Versions
IMPORTANT!
Python 3.0 is NOT completely backward-compatible with python 2.0.

Python: Versions Comparison
Basis of comparison Python 3 Python 2
Release Date 2008 2000
Function print print ("hello") print "hello*
Division of Integers
Whenever two integers are divided, you get a float
value
When two integers are divided, you always provide
integer value.
Unicode In Python 3, default storing of strings is Unicode.
To store Unicode string value, you require to define
them with "u".
Syntax The syntax is simpler and easily understandable.
The syntax of Python 2 was comparatively difficult to
understand.
Rules of ordering
Comparisons
In this version. Rules of ordering comparisons have
been simplified.
Rules of ordering comparison are very complex.
Iteration
The new Range() function introduced to perform
iterations.
In Python 2, the xrange() is used for iterations.

Python is used for:
Machine Learning
Data Science
Web Application
Development
Game Development
Python: Applications
Library Use
pymongo Database connectivity
TensorFlow Performing high-level computation
Matplotlib Plotting numerical data
Pandas Data analysis
PyGame Develop games

• Machine learning is the study of computer algorithms that can improve automatically through
experience and by the use of data. It is a part of artiﬁcial intelligence.
• Machine Learning algorithms are fed with large amount of data and then these algorithms predict
outcomes of the given problems using python.
Machine Learning Algorithms in Python:
• Linear regression
• Decision tree
• Logistic regression
• Support Vector Machines (SVM)
• Naive Bayes
Python: Versions
Python for machine learning

• Data science is an interdisciplinary field that uses scientific methods, processes, algorithms, and systems
to extract knowledge and insights from noisy, structured, and unstructured data, and apply knowledge and
actionable insights from data across a broad range of application domains.
• Python is widely used for performing different data science operations on datasets like create, read,
update, delete (CRUD), visualize, etc.
Python: Versions
Python for data science
keras
sklearn
numpy
matplotlib
tensorflow

• Python offers many frameworks from which to choose from, including Bottle.py, Flask, CherryPy, Pyramid, Django and
web2py.
• These frameworks have been used to power some of the world's most popular sites such as Spotify, Mozilla, Reddit,
etc.
Python: Versions
Python for web application

• Python provides a built-in library called pygame, which used to develop the game.
• Pygame is a cross-platform library that is used to design video and browser games.
• We can use the pygame library to make games with attractive graphics and suitable animation.
Python: Versions
Python for game development

To download python, visit the following link:
Python: Installation
https://www.python.org/downloads/

Run the installer.
01
Make sure to select
“Add Python to
PATH” option on
bottom left corner
of the installer
window.
02
In case this option
was not selected, we
have to add path to
python installation in
PATH variable
manually.
03
Keep the default
values for the
remaining steps.
04

• After installation is complete, to check the version of python installed on your system, use
“python --version” command in cmd window.
“python --version” command in cmd window

• To write and execute python code in cmd, use “py”

• An integrated development environment (IDE) is software for building applications that combines common
developer tools into a single graphical user interface (GUI).
• There are different types of IDEs like PyCharm, Visual Studio Code, etc.
• These IDEs are popularly used to develop complex applications in different frameworks.
• IDEs provide ﬂexibility to use different programming languages like python, JavaScript, C++, etc.
Python: Integrated Development Environment (IDE)

To download PyCharm, visit the following link and click on download button:
Python: Pycharm IDE Installation
https://www.jetbrains.com/pycharm/

Now, download community version installer by clicking download button below community.

Run the PyCharm
installer.
01
Click next and you
can change the
destination folder
by clicking the
browse button.
02
Click on “create
desktop icon” button
and start installation
by clicking the install
button.
03
After installation,
click the ﬁnish
button.
04

• Visual Studio Code, also commonly referred as VS Code, is a source-code editor made by Microsoft
for Windows, Linux, and macOS.
• Features include support for debugging, syntax highlighting, intelligent code completion, snippets,
code refactoring, and embedded Git.
Python: Visual Studio Code

To download vs code, visit the following link and click on download button:
Python: Visual Studio Code Installation
https://code.visualstudio.com/download

Run VScode
installer.
01
You can change
destination folder
for installation of
ﬁles.
02
Click “create desktop
icon” button.
03
Also, make sure
that you enable
“add to path” and
“Register code as
an editor for
supported ﬁles
type” button.
04
Then click on
next and install
button.
05

Create a ﬁle in vs code
with .py extension
Go to extensions > search
for “Python v2022.6.0” by
Microsoft.
Click install

• Unlike other programming languages such as java, there is no need to write too much boilerplate
code in python.
• To print a string/message on the console window, print function is used.
Our ﬁrst python program: hello world!
Python: Basics

• Write the code given in the image in a ﬁle.
• Save it by the name “demo.py”
• Files containing python source code are saved with .py extension
Python: Basics

• To execute the code present in a ﬁle, use “py ﬁle-name.py” command in cmd window.
Python: Basics

• Take a number input from user and then display that number in output.
User input in python
Python: Basics

• There is no keyword to declare variables in python.
• Variables are created by writing the name and assigning the values.
• A single variable can be used to store values of different types.
Variable
Python: Basics

• Take age input in years from user and then calculate this age in days by multiplying age by 365.
• Find error in this code below.
Python program for calculating age in days
Python: Basics

• Some of the data-types present in python are:
▪ str
▪ int, ﬂoat, complex
▪ bytes,
▪ bool
▪ list, set, tuple, range, dictionary
Variables and data types
Python: Basics
Numeric Dictionary Boolean Set
Sequence
Type
Integer Float
Complex
Number
Strings Tuple
List
Python – Data Types

• To check the type of a variable in python, type() is used.
Data types
Python: Basics
Code Output
Important!
String in python can be written using “ ” as well as ‘ ‘

Line by line execution and errors in python
Python: Basics
• In python, execution happens line by line meaning that the execution of the python program will
happen from top to down.
• Whatever line you have written at the top will be executed ﬁrst and the rest of the lines will be
executed sequentially.
• If you do not follow the python language instructions or if you make a mistake while writing the
code, then python will give you an error message in console.

Line by line execution and errors in python
Python: Basics
• An example to the errors and sequential programming is displayed below.
• In this example “variable1” at line number 3, a variable is declared; it is access at line number 2,
where an error is shown.
• The error has occurred only at line number 2, but not in line 3 and 4, which get executed after this
error. Execution was stopped at line number 2.

• Operators are used to perform operations on data, which is either received from user or manually
entered.
• The operators are divided into following groups:
▪ Arithmetic operators
▪ Assignment operators
▪ Comparison operators
▪ Logical operators
▪ Identity operators
Membership operators most commonly used operators that we will discuss here are Arithmetic,
Comparison, Assignment and Logical operators.
Operators
Python: Basics

Arithmetic operators
Python: Basics
Operator Name Example
+ Addition x + y
- Subtraction x - y
* Multiplication x * y
/ Division x / y
% Modulus x % y
** Exponentiation x ** y
// Floor division x // y

Arithmetic operators' hands on
Python: Basics

Assignment operators
Python: Basics
Operator Example Example same as below
= 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

Assignment operators' hands on
Python: Basics

Comparison operators
Python: Basics
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

Comparison operators’ hands on
Python: Basics

Logical operators
Python: Basics
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)

Logical operators' hands on
Python: Basics

Python is a programming language that was created by Guido van Rossum.
It was ﬁrst released in 1991.
It is easy to learn and easy to code language.
Unlike other programming languages such as java, there is no need to write too much boilerplate
code in python.
Use of famous code editors like Visual Studio code, PyCharm etc.
Different operators in python include Arithmetic, Comparison, Assignment and Logical operators.
Summary

Python: MCQs
Q1. Main difference between python 2 and python 3
a) Print is a statement in python 2 and a function in python 3.
b) Python 2 is syntactically diﬃcult than python 3.
c) Python 3 is not completely backward-compatible with python 2.
d) Python 3 has more usage than python 2.
e) None of the above
Q2. Predict output of code given below
a = 10
a = 20
a = 30
a = 40
print(a)
a) 10
b) 20
c) 30
d) 40

Python: MCQs
a = 30
b = 40
print(a */ b)
a) 1200
b) 0.75
c) Error message “invalid syntax”
d) 40
a = True
b = False
print((a and b) or a)
a) True
b) False
d) None of the above

Python: MCQs
a = 30
b = 40
c = 60
d = 100
print( (a <= 30 and b <=60) and (c == 60 or d <= 200))
a) True
b) False
a = 20
b = 20
c = a*b
print()
a) 400
b) 20
c) Error message “print function empty”
d) No output

Python: MCQs
a = 30
b = 40
c = 60
d = 100
print( (a <= 30 and b <=60) or (c == 60 and d <= 200))
a) True
b) False
a = 50
b = 60
c = 2000
d = 100
print( (a <= 30 or b <=60) or (c == 60 or d <= 200) )
a) True
b) False

Python: MCQs
a = 2
a **= 3
b = 20
b /= 10
print(a**b)
a) 20
b) 64.0
a = 50
b = 100
c = 200
print((a < 1000 and b > 50) and c > 10)
a) True
b) False

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