Mathematical and String-based methods for reversing the digits of an integer

reverse_int.py

import timeit
# reverse the digits of an integer i.e 1234 -> 4321
# String method turns out to be faster! (timer code if if __name__=='main' section)


def reverse_int_math(x):
    """Reverses the digits of an integer mathematically
    Args:
      x (int): integer to reverse
    Returns:
      int: x reversed
    """
    reverse = 0
    while x > 0:
        last_digit = x % 10
        # *10 to 'make space' for last_digit
        reverse = (reverse * 10) + last_digit
        x //= 10
    return reverse


def reverse_int_string(x):
    """Reverses the digits of an integer by casting to a string, reversing,
    then casting back to an int.
    Args:
      x (int): integer to reverse
    Returns:
      int: x reversed
    """
    return int(str(x)[::-1])


def reverse_int_binary(x):
    """Reverses the digits of an integer by casting to a string, reversing,
    then casting back to an int.
    Args:
    x (int): integer to reverse
    Returns:
    int: x reversed
    """
    res = 0
    while x > 0:
        res = res << 1
        res = res | (x & 1)
        x = x >> 1
    return res


if __name__ == '__main__':
    print('Mathematical method:')
    print(timeit.timeit('reverse_int_math(123456723452346547457)',
                        setup='from __main__ import reverse_int_math'))
    print('String method:')
    print(timeit.timeit('reverse_int_string(123456723452346547457)',
                        setup='from __main__ import reverse_int_string'))
    print('Binary method:')
    print(timeit.timeit('reverse_int_binary(123456723452346547457)',
                        setup='from __main__ import reverse_int_binary'))