While Loop in Python

September 15, 2023

while loop in python

While Loop

While loop is entry control loop.Disadvantage of “For” loop is we cannot use condition in the loop. In python , if we need a loop which works on condition then we go with while loop. Also if we need an infinite loop we can use while loop.

While Loop in Python

A while loop in Python is used to repeatedly execute a block of code as long as a specified condition is True. The loop continues executing as long as the condition remains True, and it terminates when the condition becomes False. 

Syntax of While loop

while(condition):
        #statements

Syntax of infinite while loop

while(True):
        #statements
          (or)
while(1):
        #statements

Working 

  • Step 1: Take while loop with a condition
  • Step 2:  Evaluate expression in Boolean form
  • Step 3: If  boolean condition is True then it go inside the loop , if boolean condition is False then it terminates the loop
  • Step 4: It execute the statements inside the loop 
  • Step 5: Step 3 is repeated until the condition becomes False.

Python Code:

Run 
a=1
b=10
#loop with True condition
while(a<=b):
    print(a,end=" ")
    a+=1  #for incrementing a
print("\nValues at the point of terminating loop are : a={} and b={}".format(a,b))
Output:
1 2 3 4 5 6 7 8 9 10
Values at the point of terminating loop are : a=11 and b=10

Nested While loop

Run 
#printing a box pattern using nested while loop
i,n=0,5
while(i < n):
    j=0
    while(j < n):
        print("*",end=" ")
        j+=1
    i+=1
    print()
Output:
* * * * *
* * * * *
* * * * *
* * * * *
* * * * *

Decision making in Python

If-else statement in Python

AND, OR and NOT in Python

Loops in Python

For Loops in Python

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