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Loops in PYTHON (For loop and While loop)

Why do we need loops in python ? And how it makes our codes more simpler and shorter ? 

Sometimes we want to repeat a set of statements in our programme for instance.

If we want to print 1 - 1000 in our python programme. Then it is not easy to print every number separately. Thus we need loops because using only 2-3 lines of code we can do this.

Loops make it easy for a programmer to tell the computer, which set of instruction to repeat as much as times we want.


Types of loops in Python :-

1.) While loop

2.) For loop

We will look into these one by one !

1.) WHILE LOOP :-

The syntax of a while loop looks like this :

while(condition):
    #code accordingly
    #this code will keeps working until the condition is satisfied

In while loops, the condition is checked first. If comes true, the body code will starts running else not.
If the loop is started it will runs until the condition becomes false.

Now lets write a code to print all the numbers from 1 - 100 :-



Now another code to print all the numbers from 1-100 which are divisible 3 :-






2.) FOR LOOP :-

A for loop is used to iterate through a sequence like list, tuple, or string.
The syntax of the for loop is :-

mylist  =  [4, 2, 8, 4, 78]
for i in range(0, len(mylist)+1):
     print(mylist[i])

Now we will try the same programmes for For loop which were used in the while loop section.

First code to print the number from 1-100 :-



Now the second code is to print all the numbers from 1-100 which are divisible by 3 :-




Now we have the basic knowledge of the loops and rest depends on your practice.

What are break statements in python loops ? And to use them in our code ?

Break is used to come out of the loop when encountered. It instructs the programme to exit the loop now.

Use in code :-





Hope you like this tutorial. Please share it with your friends and help them learning python. In the next tutorial we will learn about function and recursion in python.



John Veer
Contact mail id  -  john.veer.utube@gmail.com
Thanks for reading !
                                                                         

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