Python Basics

• Python is interpreted language, and statements are executed line by line.

• source code is stored in .py file extension.

History

From python, we can make -

• Games -

  • Flappy bird using PyGame

  • Snake game using PyGame

• Websites- in the backend using Python flask

• GUI (Graphics User Interface)

• Natural Language Processing (speaking to/with the machine)

Python used By :

• Instagram Backend

• Facebook Backend

• Youtube Custom

• Intel

• IBM

• NASA

• JPMorgan

Developed By:

• Guido Van Rossum

Name Script Taken From:

• "Monty Python's Flying Circus" from a BBC comedy series.

How to run a python file in CMD of the current directory :

python filename.py

How to install External Module:

• Open PowerShell

• Write pip install module_name

• Run python REPL(Run Evaluate Print Loop) by writing Python

Run Python in PowerShell:

python

import flask

(Shows "No Error")

import random

"No Error" - (It is Built-in Module)

import pandas

Shows "Error" - (It is Not Found) We have to download from the internet.

exit()

• Go to Docs Reference Python Built-in Module

Important Remarks:

• pip - Package Manager of python

• You can also use another software like - V.S.Code, Sublime Text, Atom.

• Don't use the module name as "Python file" Names like a flask, pandas e.t.c

• You can use multiple interpreters like python 3.9, 3.8, 3.7 e.t. simultaneously in Pycharm

• Module:

  • Built-in Module - already in python

  • External Module - download from the internet

Project Example:

• Print Receipt for every client of a company which has to give only name, phone no. and address then it prints their receipt. (only required to fill detail then it converts into receipt) -> (Payment Calculator)

Using Python REPL as a calculator

Run Python in PowerShell:

20+56+25

Out[1]: 101

56*10

Out[2]: 560

10*4 + 5*9 + 36*8

Out[3]: 373

36/8     # Float Value

Out[5]: 4.5

25/5    # Float Value

Out[6]: 5.0

25//5    # Int Value

Out[7]: 5