Python: A small function to make a string of digits for numbering columns in the output.

numbar.py

def numbar(n: int) -> str:
    """
    Make a string of digits for numbering columns in the output.  Column
    numbering begins with zero.  If the number of columns require more 
    place values, newlines are used to make multiple rows in the output.
    E.g., if `n <= 10`, there will be one row of output, but if
    `10 < n <= 100`, there will be two rows of output, etc.
    """
    
    rows = len(str(n - 1))
    return '\n'.join(
        ''.join(j[i] for j in 
                [f'{m:0{rows}}' for m in range(n)]) 
        for i in range(rows))

print(numbar(10))
# 0123456789

print(numbar(42))
# 000000000011111111112222222222333333333344
# 012345678901234567890123456789012345678901

print(numbar(101))
# 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001
# 00000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990
# 01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890