While loop

What is While loop in Python?

• A While loop in Python is used to execute a set of statements/ iterate over a block of code repeatedly as long as the given condition is true.

• While loop is preferred when we don't know the number of iterations.

Syntax:

                    while condition:

                            body statements

• The body statement of the while loop is separated from the rest of the code using indentation [tab].

Flow/Working of While loop:

• In the While loop, the Given condition is checked first. If the condition is true then only the loop starts to execute the body statements.

• After one iteration, the condition is checked again and the process continues until the condition evaluates to False.

• Python interprets any non-zero value as TRUE. None and 0 are interpreted as False.

While loop - Example

Output

While loop with Else:

• Just like for loop, While loop can also have an optional 'else' block.

• The 'else' block will be executed only when the given condition becomes false.

• Else block won't be executed for cases like break out of the loop (terminated by break statement) or if an exception is raised.

While loop - else block

Output

Nested While loop:

• A While loop inside another while loop is called nested while loop.

• See the below example to understand this concept.

Nested While Loop

Output