Python While Loop Exercise - Age and Input Validation | Code Example

Step-by-step solution for Python while loop exercise age and input validation. Learn how to solve this problem efficiently with clear explanations and example code. Perfect for beginners!

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Solution

while True:
    age_input = input("Enter your age: ")
    if not age_input.isdigit():
        print("Please enter a valid number.")
        continue

    age = int(age_input)
    if age <= 0:
        print("You haven't been born yet!")
        continue
    break

print()
name = input("Enter your name: ")
print(f"Your name is {name} and you are {age} years old.")
print()

exercise = input("Do you like to exercise? (Y/N) only: ").strip().upper()
while exercise != "N":
    print("Choose either Yes (Y) or No (N) only!")
    exercise = input("Do you like to exercise? (Y/N): ").strip().upper()

print()
print("Nice")

Explanation

Here’s a line-by-line explanation of the provided code:

1. Infinite Loop for Age Input

while True:

• Starts an infinite loop that will keep running until explicitly broken (break).

2. Prompt User for Age Input

    age_input = input("Enter your age: ")

• Asks the user to enter their age and stores it in age_input.

3. Check if Input is a Valid Number

    if not age_input.isdigit():
        print("Please enter a valid number.")
        continue

• Checks if age_input is not a digit (i.e., not a valid number).
  • If not, it prints an error message and continue restarts the loop.

4. Convert Input to Integer and Validate Age

    age = int(age_input)
    if age <= 0:
        print("You haven't been born yet!")
        continue

• Converts age_input to an integer (age).
• Checks if age is ≤ 0 (invalid age).
  • If so, it prints a message and continue restarts the loop.

5. Exit the Loop if Age is Valid

    break

• If the input passes all checks, break exits the loop.

6. Print a Blank Line for Readability

print()

• Prints a newline for better formatting.

7. Prompt User for Name and Display

name = input("Enter your name: ")
print(f"Your name is {name} and you are {age} years old.")
print()

• Asks for the user’s name and stores it in name.
• Prints the name and age in a formatted string.
• Prints another blank line.

8. Ask if User Likes Exercise (Initial Prompt)

exercise = input("Do you like to exercise? (Y/N) only: ").strip().upper()

• Asks the user if they like exercise (expecting Y or N).
• .strip() removes extra whitespace.
• .upper() converts input to uppercase for case-insensitive comparison.

9. Validate Exercise Input (Must be ‘N’)

while exercise == "Y":
    print("Choose either Yes (Y) or No (N) only!")
    exercise = input("Do you like to exercise? (Y/N): ").strip().upper()

• If the user enters "Y", the loop forces them to re-enter until they provide "N".
  • (Note: This logic is backwards—it should check for invalid inputs instead.)

10. Print Final Message

print()
print("Nice")

• Prints a blank line followed by "Nice".

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