Python While Loops
In Python, a
while loop is used to repeatedly execute a block of code as long as a certain condition is true. The general syntax of a
while loop in Python is as follows:
while condition: # Code to be executed
The condition is a Boolean expression that determines whether the loop should continue executing or not. If the condition is initially false, the code inside the loop will not be executed at all.
Here’s an example that demonstrates a simple
while loop that prints numbers from 1 to 5:
count = 1 while count <= 5: print(count) count += 1
In this example, the variable
count is initially set to 1. The condition
count <= 5 is evaluated before each iteration. As long as the condition is true, the code inside the loop (printing the value of
count) will be executed. After each iteration, the value of
count is incremented by 1 using the
+= operator. The loop continues until the condition becomes false when
count exceeds 5.
It’s important to ensure that the condition within the
while loop will eventually become false; otherwise, you may end up with an infinite loop, which can cause your program to hang or crash. To avoid this, you can include additional logic within the loop to modify the condition or use
break statement to exit the loop based on certain conditions.
Here’s an example of using a
while loop with a
break statement to simulate a simple guessing game:
secret_number = 42 while True: guess = int(input("Enter your guess: ")) if guess == secret_number: print("Congratulations! You guessed it.") break else: print("Wrong guess. Try again.")
In this example, the
while loop continues indefinitely (
True is always true), but it can be exited using the
break statement when the user guesses the correct number.
Remember to be cautious while using
while loops to avoid infinite loops and ensure that the condition is appropriately modified within the loop to eventually become false.