n_digits.py

import math
from itertools import islice
from typing import Iterable


def first_n_digits(num: int, n: int) -> Iterable[int]:
    """
    Returns an iterable of the first `n` digits (left to right) in `num`

    Examples:
        >>> list(first_n_digits(12345, 5))
        [1, 2, 3, 4, 5]
        >>> list(first_n_digits(12345, 4))
        [1, 2, 3, 4]
        >>> list(first_n_digits(12345, 3))
        [1, 2, 3]
        >>> list(first_n_digits(12345, 2))
        [1, 2]
        >>> list(first_n_digits(12345, 1))
        [1]
    """
    return (
        (num // (10 ** i)) % 10
        for i in islice(range(math.ceil(math.log10(num)) - 1, -1, -1))
    )