While Loop in Python

 

 What is Use of while Loop in Python:

while loop is used to execute a block of statements repeatedly until condition does not satisfy.

 When condition becomes false the statements written in block will get execute.

Syntax:

while expression:

statement(s)

 

In the above syntax statement may be single or multiple statements. The test condition may have any condition. The while loop will get iterate again and again until condition doesnot satisfy.

 In Python all the statements indented by the same number of characters and spaces after the block.

 

For example:

 # To display first 10 numbers on screen using while loop in python

n=10

i=0

print (" First n numbers are")

while i<n:

  i=i+1

  print(i)

O/P:

First n numbers are 1 2 3 4 5 6 7 8 9 10

In above example first 10 numbers are displayed on screen by using while loop.
First i is initialized with 0 and then it is repeatedly executed until final result does not meet.

Once condition becomes false i.e. when get 11 the iteration will stop and execute related statement.

In every iteration the number will be incremented by 1.

# Sum of n natural numbers using while loop

n=int(input("Enter Namer\t"))

sum=0

i=1

while i<=n :

    sum=sum+i

    i=i+1 

    

    print(sum)

 

O/P:

Enter Namer     10

1

3

6

10

15

21

28

36

45

55

 

# Sum of n even natural numbers using while loop

n=int(input("Enter Namer\t"))

sum=0

i=1

print("The sum of n even numbers is:\t")

while i<=n :

    if i%2==0:

        sum=sum+i

    i=i+1 

    

    print(sum)

 

O/P:

Enter Namer     10

The sum of n even numbers is:   30

 

# Fibonacci Series using while loop

n=int(input("Enter number to display fibonacci series\t"))
a=0
b=1 
i=1 
c=0
while i<=n:
    i=i+1 
    a=b
    b=c
    c=a+b 
    print(c)
O/P:
Enter number to display fibonacci series 10
1
1
2
3
5
8
13
21
34
55