Tutorial Full Easy Learning Python 3 4 From Begin to Advance Geeky Shares

Python was developed by Guido van Rossum in the early 1990s and its latest version is 3.10.5, we can simply call it Python3. Python 3.0 was released in 2008. and is interpreted language i.e it's not compiled and the interpreter will check the code line by line. This article can be used to learn the very basics of Python programming language. So before moving on further.. let's do the most popular 'HelloWorld' tradition 😛 and hence compare Python's Syntax with C, C++, and Java ( I have taken these 3 because they are the most famous and mostly used languages).

Python3

Note: Please note that Python for its scope doesn't depend on the braces ( { } ), instead it uses indentation for its scope. Let us start with our basics of Python where we will be covering the basics in some small sections. Just go through them and trust me you'll learn the basics of Python very easily.

Introduction and Setup

1. If you are on Windows OS download Python by Clicking here and now install from the setup and in the start menu type IDLE.IDLE, you can think it as a Python's IDE to run the Python Scripts. It will look somehow this :
2. If you are on Linux/Unix-like just open the terminal and on 99% linux OS Python comes preinstalled with the OS.Just type 'python3' in terminal and you are ready to go. It will look like this :

          The " >>> " represents the python shell and its ready to take python commands and code.        

Variables and Data Structures

In other programming languages like C, C++, and Java, you will need to declare the type of variables but in Python you don't need to do that. Just type in the variable and when values will be given to it, then it will automatically know whether the value given would be an int, float, or char or even a String.

Python3

myNumber = 3

print (myNumber)

myNumber2 = 4.5

print (myNumber2)

myNumber = "helloworld"

print (myNumber)

See, how simple is it, just create a variable and assign it any value you want and then use the print function to print it. Python have 4 types of built-in Data Structures namely List, Dictionary, Tuple, and Set.

List is the most basic Data Structure in python. List is a mutable data structure i.e items can be added to list later after the list creation. It's like you are going to shop at the local market and made a list of some items and later on you can add more and more items to the list.
append() function is used to add data to the list.

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nums = []

nums.append( 21 )

nums.append( 40.5 )

nums.append( "String" )

print (nums)

Output

[21, 40.5, 'String']

Python3

Dict = []

Dict = { 1 : 'Geeks' , 2 : 'For' , 3 : 'Geeks' }

print ( Dict )

Output

{1: 'Geeks', 2: 'For', 3: 'Geeks'}

Python3

tup = ( 'Geeks' , 'For' , 'Geeks' )

print (tup)

Output

('Geeks', 'For', 'Geeks')

Python3

myset = set ([ "Geeks" , "For" , "Geeks" ])

print (myset)

Comments:

# is used for single line comment in Python """ this is a comment """ is used for multi line comments

Input and Output

In this section, we will learn how to take input from the user and hence manipulate it or simply display it. input() function is used to take input from the user.

Python3

name = input ( "Enter your name: " )

print ( "hello" , name)

Output:

hello harssh

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num1 = int ( input ( "Enter num1: " ))

num2 = int ( input ( "Enter num2: " ))

num3 = num1 * num2

print ( "Product is: " , num3)

Output:

Enter num1: 8 Enter num2: 6 ('Product is: ', 48)

Selection

Selection in Python is made using the two keywords 'if' and 'elif'(elseif) and else

Python3

num1 = 34

if (num1> 12 ):

print ( "Num1 is good" )

elif (num1> 35 ):

print ( "Num2 is not gooooo...." )

else :

print ( "Num2 is great" )

Functions

You can think of functions like a bunch of code that is intended to do a particular task in the whole Python script. Python used the keyword 'def' to define a function.
Syntax:

def function-name(arguments):            #function body

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def hello():

print ( "hello" )

print ( "hello again" )

hello()

hello()

Output

hello hello again hello hello again

Now as we know any program starts from a 'main' function…lets create a main function like in many other programming languages.

Python3

def getInteger():

result = int ( input ( "Enter integer: " ))

return result

def Main():

print ( "Started" )

output = getInteger()

print (output)

if __name__ = = "__main__" :

Main()

Output

Started Enter integer: 0

Iteration (Looping)

As the name suggests it calls repeating things again and again. We will use the most popular 'for and while' loop here.

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for step in range ( 5 ):

print (step)

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step = 0

while (step < 5 ):

print (step)

step = step + 1

Modules

Python has a very rich module library that has several functions to do many tasks. You can read more about Python's standard library by Clicking here
'import' keyword is used to import a particular module into your python code. For instance consider the following program.

Python3

import math

def Main():

num = - 85

num = math.fabs(num)

print (num)

if __name__ = = "__main__" :

Main()

These are some of the basics of the Python programming language and I will be covering both the intermediate and advanced level Python topics in my upcoming articles.

This article is contributed by Harsh Wardhan Chaudhary. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks. Your article will be reviewed first by the Geeks for Geeks team before publishing.

Please write comments if you find anything incorrect, or if you want to share more information about the topic discussed above.

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Source: https://www.geeksforgeeks.org/python-3-basics/

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