Validate mobile number in Python

Validate mobile number in Python

 

Consider we are validating an Indian mobile number it has at most 13 digits with +91 before the 10 digit number which starts with the starting number between 7-10.

If the user enters the 10-digit number for which the starting number is between 7-10 the number is treated as valid.

The code below is written in such a way that it gives us a valid output if it is a 13-digit number that starts with +916,+917,+918, or +919 as well as if the number consists of 10 digits starting with 6,7,8 or 9.

 

def validate_phone(number):
    """
    Validate a phone number.

    A valid phone number:
    - Can be a 13-digit number starting with "+916", "+917", "+918", or "+919"
    - Can be a 10-digit number starting with 6, 7, 8, or 9

    Args:
    number (str): The phone number to validate.

    Returns:
    str: "Valid" if the number is valid, otherwise "Invalid".
    """
    # Check if the number is all digits or starts with '+' and the rest are digits
    if number.isdigit() or (number.startswith('+') and number[1:].isdigit()):
        # Check if the number is a 13-digit number starting with "+916", "+917", "+918", or "+919"
        if len(number) == 13 and (number.startswith("+916") or number.startswith("+917") or number.startswith("+918") or number.startswith("+919")):
            return "Valid"
        # Check if the number is a 10-digit number starting with 6, 7, 8, or 9
        elif len(number) == 10 and number[0] in "6789":
            return "Valid"
    # If none of the conditions are met, return "Invalid"
    return "Invalid"

# Example usage
if __name__ == "__main__":
    phone_input = input("Enter the phone number: ")
    print(validate_phone(phone_input))

1.Function Definition and Docstring:

• The function validate_phone is defined to take one parameter: number.
• A docstring is provided to explain the purpose of the function, the expected argument, and the return value.

2.Check for Valid Digits:

• The if number.isdigit() or (number.startswith('+') and number[1:].isdigit()): line checks if the input number consists entirely of digits or if it starts with a ‘+’ followed by digits.
• number.isdigit() ensures the number is all digits.
• (number.startswith('+') and number[1:].isdigit()) allows for a ‘+’ at the beginning and checks if the rest of the string is digits.

3.Check for 13-Digit Number with Specific Prefixes:

• if len(number) == 13 and (number.startswith("+916") or number.startswith("+917") or number.startswith("+918") or number.startswith("+919")):
• len(number) == 13 checks if the length of the number is 13 characters.
• number.startswith("+916") or ... ensures the number starts with one of the specified prefixes: “+916”, “+917”, “+918”, or “+919”.
• If both conditions are met, the function returns “Valid”.

4.Check for 10-Digit Number Starting with 6, 7, 8, or 9:

• elif len(number) == 10 and number[0] in “6789”:
• len(number) == 10 checks if the length of the number is 10 characters.
• number[0] in "6789" ensures the first digit is one of 6, 7, 8, or 9.
• If both conditions are met, the function returns “Valid”.

5.Return “Invalid” for Non-Matching Numbers:

• If none of the conditions are met, the function returns “Invalid”.

6.Example Usage:

• The script includes a main guard: if __name__ == "__main__":.
• This allows the script to be run as a standalone program.
• phone_input = input("Enter the phone number: ") prompts the user to input a phone number.
• print(validate_phone(phone_input)) prints the result of the validate_phone function based on the user’s input.

Output:

Enter the phone number: +916784321021
Valid

Enter the phone number: 9347123482
Valid

Enter the phone number: 96388929aa
Invalid