Display a list of lists as a simple text table with rows, columns and an optional header.

print_table.py

from math import log10
from typing import Sequence

def print_table(rows: Sequence[Sequence], hdr=True, rownums=True) -> None:
    """Display as a simple text table; rows, columns & optional header.

    rows:
        Rows & columns where each cell object is a string or can be
        converted into a string.

    hdr:
        Indicates that the first row contains header labels

    rownums:
        Adda a new column at the beginning of the table containing
        row numbers.

    raises:
        TypeError if a cell can't be coverted to a string.

    tailored for low-complexity:

        * If rows differ in numbers of columns then blank cells will
          be padded to ensure every row has the same number of columns.

        * The text in the cells will be always be left aligned;
          doesn't support other alignments.

        * The borders are always drawn with pluses (+) and dashes (-);
          doesn't support border customization

        * Doesn't support word wrapping in cells.

        * Doesn't check and limit column sizes to fit terminal width.

        * Doesn't support column or row spanning.

    >>> table = [
    ...    ['Element', 'Symbol', 'Upper Crustal Abundance (ppm)'],
    ...    ['Cerium', 'Ce', 64],
    ...    ['Lanthanum', 'La', 30]
    ... ]
    >>> print_table(table)
    +---+-----------+--------+-------------------------------+
    |   | Element   | Symbol | Upper Crustal Abundance (ppm) |
    +---+-----------+--------+-------------------------------+
    | 1 | Cerium    | Ce     | 64                            |
    | 2 | Lanthanum | La     | 30                            |
    +---+-----------+--------+-------------------------------+

    >>> print_table(table, rownums=False)
    +-----------+--------+-------------------------------+
    | Element   | Symbol | Upper Crustal Abundance (ppm) |
    +-----------+--------+-------------------------------+
    | Cerium    | Ce     | 64                            |
    | Lanthanum | La     | 30                            |
    +-----------+--------+-------------------------------+

    >>> table = table[1:]
    >>> print_table(table, hdr=False)
    +---+-----------+----+----+
    | 1 | Cerium    | Ce | 64 |
    | 2 | Lanthanum | La | 30 |
    +---+-----------+----+----+

    >>> print_table(table, hdr=False, rownums=False)
    +-----------+----+----+
    | Cerium    | Ce | 64 |
    | Lanthanum | La | 30 |
    +-----------+----+----+

    >>> table = [['Element', 'Symbol', 'No Data'], ['Cerium', 'Ce']]
    >>> print_table(table)
    +---+---------+--------+---------+
    |   | Element | Symbol | No Data |
    +---+---------+--------+---------+
    | 1 | Cerium  | Ce     |         |
    +---+---------+--------+---------+
    """
    # ensure each row has the same number of columns
    uniq_num_cols = {len(i) for i in rows}
    if len(uniq_num_cols) > 1:
        num_cols = max(uniq_num_cols)
        rows = [i + [''] * (num_cols - len(i)) for i in rows]

    # add a column containing the row numbers
    if rownums:
        rows = rows[:]
        if hdr:
            rows[0] = [''] + rows[0]
        for num in range(hdr, len(rows)):
            rows[num] = [num + (not hdr)] + rows[num]

    try:
        widths = [max(len(str(j)) for j in i) for i in zip(*rows)]
    except TypeError:
        raise

    # draw table
    res = []
    for row in rows:
        cols = ' | '.join(str(j).ljust(k) for j, k in zip(row, widths))
        res.append(f'| {cols} |')
    hsep = ['+%s+' % '+'.join('-' * (i + 2) for i in widths)]
    if hdr:
        res = res[:1] + hsep + res[1:]
    print('\n'.join(hsep + res + hsep))