Question

question : Phone Number CheckingAlice has been having trouble with people filling her website’s form incorrectly, especially with phone numbers. She’d like tomake sure a user’s phone number input only has digits (other than -) and is exactly 10 digits long.Finishvalidphonenumber(string)such that the function returns True if a phone number is valid, and False if not.

def valid_phone_number(number: str) -> bool:
    """
    Return True if the number is a valid phone number. A valid phone number:
    1) Has exactly 10 digits (we are excluding the country code)
    2) Only has digits (no alphabets or special characters)
    3) May have "-" to split numbers. Example: 0123456789 and 012-345-6789 are
    BOTH valid

    Do *not* use loops for this problem. Try to make sure you only use built-ins

    Hint: you will need 3 built-in string methods

    >>> valid_phone_number("0123456789")
    True

    >>> valid_phone_number("012-345-6789")
    True

    >>> valid_phone_number("01-23-45-67-89")
    True
    """
    # TODO: do some checking here

    # change this
    return True

#### Part 2: String Functions with loops ###

Answer 1

def valid_phone_number(number: str) -> bool:
    """
    Return True if the number is a valid phone number. A valid phone number:
    1) Has exactly 10 digits (we are excluding the country code)
    2) Only has digits (no alphabets or special characters)
    3) May have "-" to split numbers. Example: 0123456789 and 012-345-6789 are
    BOTH valid

    Do *not* use loops for this problem. Try to make sure you only use built-ins

    Hint: you will need 3 built-in string methods

    >>> valid_phone_number("0123456789")
    True

    >>> valid_phone_number("012-345-6789")
    True

    >>> valid_phone_number("01-23-45-67-89")
    True
    """
    number = number.replace('-', '')
    return len(number) == 10 and number.isdigit()