Python Program to Validate a Date

This Python program checks if a given date is valid or not. It verifies if the provided date is in a correct format and falls within the valid range of dates.

Problem statement

You are required to write a Python program that validates a given date and determines if it is a valid date or not.

Python Program to Validate a Date

def is_valid_date(date_string):
    try:
        # Split the date into day, month, and year
        day, month, year = map(int, date_string.split('/'))

        # Check if the year is within the valid range
        if year < 1 or year > 9999:
            return False

        # Check if the month is within the valid range
        if month < 1 or month > 12:
            return False

        # Check if the day is within the valid range for the given month and year
        if day < 1 or day > 31:
            return False

        # Check for specific month and day validity
        if month in [4, 6, 9, 11] and day > 30:
            return False

        if month == 2:
            if year % 4 == 0 and (year % 100 != 0 or year % 400 == 0):
                if day > 29:
                    return False
            elif day > 28:
                return False

        return True
    except ValueError:
        return False

# Test the function
date_input = input("Enter a date (in dd/mm/yyyy format): ")
if is_valid_date(date_input):
    print("Valid date")
else:
    print("Invalid date")

How it works

1. The is_valid_date() function takes a date_string as input, which represents the date in the format “dd/mm/yyyy”.
2. The function attempts to split the date string into day, month, and year by using the split() method and converting the resulting parts to integers.
3. It first checks if the year is within the valid range of 1 to 9999. If not, it returns False.
4. It then checks if the month is within the valid range of 1 to 12. If not, it returns False.
5. Next, it checks if the day is within the valid range of 1 to 31. If not, it returns False.
6. For months with only 30 days (April, June, September, November), it checks if the day is greater than 30 and returns False if it is.
7. For February, it checks if the year is a leap year (divisible by 4 and not divisible by 100, except if divisible by 400). If it is a leap year, it checks if the day is greater than 29 and returns False if it is. If it is not a leap year, it checks if the day is greater than 28 and returns False if it is.
8. If none of the above conditions are met, it returns True, indicating that the date is valid.
9. Finally, the program prompts the user to enter a date in the “dd/mm/yyyy” format and calls the is_valid_date() function to check if it is a valid date. It prints the corresponding message based on the validation result.

Input / Output