Python Validate User Input
Example 1
isalpha
while True: name = input("Enter the player's name: ") if name.isalpha() and len(name) > 1: break else: print("Invalid name. Please enter a valid name with alphabetic characters only.")print(f"The player's name is {name}.")Example 2
integer
while True: try: home_runs = int(input("Enter the number of home runs: ")) if 0 <= home_runs <= 80: break else: print("Please enter the correct number of home runs (0-80).") except ValueError: print("Invalid input. Please enter a whole number.")
print(f"The number of home runs is {home_runs}.")Example 3
float
while True: try: average = float(input("Enter the player's batting average (0.000 - 0.500): ")) if 0.000 <= average <= 0.500: break else: print("Please enter a batting average between 0.000 and 0.500.") except ValueError: print("Invalid input. Please enter a number between 0.000 and 0.500.")print(f"The player's batting average is {average}.")Example 4
custom invalid characters not using isalpha
invalid_chars = ('.', '/', '!', '@', '#', '1', '2', '3')while True: name = input("Enter the player's name: ") invalid_chars_count = 0 for char in invalid_chars: if char in name: invalid_chars_count += 1 if invalid_chars_count > 0 or len(name) < 1: print() print("invalid!") else: break
print (name)Example 5
date example
from datetime import datetimeDefine the valid months for the baseball season
February (2) to October (10)
valid_months = list(range(2, 11))while True: game_date_input = input("Enter the baseball game date (MM/DD/YYYY): ") try: # Attempt to parse the date input game_date = datetime.strptime(game_date_input, "%m/%d/%Y") # Check if the month of the date is within the valid range if game_date.month in valid_months: print(f"Valid date: {game_date.date()}") print("Thank you! The game date is set.") break else: print("The date must be between February and October.") except ValueError: print("Invalid date format. Please enter the date in MM/DD/YYYY format.")
Ryan is a Data Scientist at a fintech company, where he focuses on fraud prevention in underwriting and risk. Before that, he worked as a Data Analyst at a tax software company. He holds a degree in Electrical Engineering from UCF.