Input Validation with if

User input is useful, but it should not be accepted blindly. This Block shows you how to validate one input attempt with clear if, elif, and else branches. You will check converted numbers against realistic ranges, prepare text with strip() and lower(), and give feedback that tells the user exactly what needs to change.

What you will learn:

• Validate converted numeric input with inclusive boundaries
• Normalize text before checking exact choices
• Use in and not in for string membership checks
• Build ordered validation rules with if, elif, and else
• Write clear rejection messages and keep success in the correct branch
• Avoid common mistakes with raw input, range logic, and cleaned values

By the end, you will be able to turn one piece of user input into a clear decision: accept it when it follows the rules, or explain why it does not.