If you want to execute a group of statements multiple times then you should go for iterative statements.
Python supports 2 types of iterative statements.
- while loop
- for loop
If you want to execute a group of statements iteratively until some condition false, then you should go for while loop.
The syntax of while loop in Python programming language as follows,
while expressions: statements
You can print numbers from 1 to 10 by using while loop as follows.
x=1 while x <=10: print(x) x=x+1 Output 1 2 3 4 5 6 7 8 9 10
Eg: To display the sum of first n numbers,
n=int(input("Enter number:")) sum=0 i=1 while i<=n: sum=sum+i i=i+1 print("The sum of first",n,"numbers is :",sum) Output Enter number:5 The sum of first 5 numbers is : 1 The sum of first 5 numbers is : 3 The sum of first 5 numbers is : 6 The sum of first 5 numbers is : 10 The sum of first 5 numbers is : 15
Using else statement you can run a block of code once when the condition no longer is true,
i = 1 while i < 5: print(i) i += 1 else: print("i is no longer less than 5") Output 1 2 3 4 i is no longer less than 5
Using break statement you can stop the loop even if the while condition is true,
i = 1 while i < 5: print(i) if i == 2: break i += 1 Output 1 2
Using continue statement you can stop the current iteration, and continue with the next,
i = 0 while i < 5: i += 1 if i == 2: continue print(i) Output 1 3 4 5
Read Also : Python – Decision Making ( IF ELSE Statement )