While Loop

What is a Python while loop?

A Python while loop is a programming construct that allows you to execute a block of code repeatedly as long as a condition is True. The syntax for a while loop is as follows:

Python

while condition:
  code block
 

The condition can be any Boolean expression. If the condition evaluates to True, the code block is executed. If the condition evaluates to False, the code block is skipped and the loop terminates.

Examples:

Python

# Print the numbers from 1 to 10
i = 1
while i <= 10:
  print(i)
  i += 1

# Keep asking the user for a number until they enter a number greater than 10
number = 0
while number <= 10:
  number = int(input("Enter a number: "))
 

How to use while loops effectively

Here are some tips for using while loops effectively:

• Use descriptive variable names and comments to make your code more readable and easier to maintain.
• Be careful not to write infinite loops. Infinite loops are loops that will never terminate, which can cause your program to crash.
• Use break and continue statements to control the flow of your loops.

Break and continue statements

The break statement is used to terminate a loop prematurely. The continue statement is used to skip the rest of the current iteration of a loop and start the next iteration.

Examples:

Python

# Print the numbers from 1 to 10, but break the loop when the number reaches 5
i = 1
while i <= 10:
  print(i)
  if i == 5:
    break
  i += 1

# Keep asking the user for a number until they enter a number greater than 10, but skip the rest of the current iteration of the loop if the user enters a negative number
number = 0
while number <= 10:
  number = int(input("Enter a number: "))
  if number < 0:
    continue
  print("The number is greater than 10.")
 

Conclusion

Python while loops are a powerful tool that can be used to execute a block of code repeatedly as long as a condition is True. By understanding how to use while loops effectively, you can write more efficient and readable Python code.