Python3 While loop

Python While Loop

WHILE Loop :

The while loop in python is used to iterate over a block of code as long as the test expression(condition) is true

Syntax::

while test_expression:

body of while

* The body of the loop is entered only if the test_expression is true.

* After one iteration, the test_expression is checked again.

* This process proceeds until the test_expression is false.

Flow Chart :

Eg:

lst=[10,20,30,40,50]

product=1
index=0

while index<len(lst):
product*=lst[index]
index+=1

print("Product is:{}".format(product))

output: Product is 14400000

While loop with else:

This is same as for loop, we can use else block with while loop as well.

* The else part is executed if the condition of while loop evaluates to false. The while loop can be terminated with the break statement.

* In such case ,this is ignored. Hence, a while loop's else part runs if no break occurs and the condition is false.

Eg:

num=[1,2,3]
index=0
while iindex<len(num):
print(number[index])
index+=1
else:
print("no item left in the list")

output::

1
2
3
no item left in the list

Program to check given number is prime or not:

num= int(input("enter a number:")

isdivisible=False;

i=2;

while i<num:

if num % i==0:

isdivisible=True;

print("{} is divisible by {}".format(num,i))

i+=1;

if isdivisible:

print("{} is not a prime number" .format(num))

else:

print("{} is a prime number" .format(num))

output: enter a number 16

16 is divisible by 2
16 is divisible by 4
16 is divisible by 8
16 is not a prime number

If you have any doubts pls comment

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