Create reStructuredText complex table from list of dictionaries

dict_to_rst_table.py

# coding: utf-8
"""Purpose: Create reStructuredText complex table from list of dictionaries

Created: 2019-09-05
Authors: dhohls <dhohls@csir.co.za> Derek Hohls

Example:

code::

    string = "Please type this:\n'The quick brown fox jumps over the lazy dog.'"
    one = {'Item':'Simple','Details':'One-liner'}
    two = {'Item':'Typing test','Details':string}
    result = create_table([one, two], column_widths=[15, 30])
    for line in result:  print(line)

result::

    +---------------+------------------------------+
    |Item           |Details                       |
    +===============+==============================+
    |Simple         |One-liner                     |
    +---------------+------------------------------+
    |Typing test    |Please type this:             |
    |               |'The quick brown fox jumps    |
    |               |over the lazy dog.'           |
    +---------------+------------------------------+

"""
import collections


DEFAUlT_COL_WIDTH = 15

def split_string(string, limit, sep=" "):
    """Split a string by whitespace and prevent splitting words.
    
    Args:
        string (str): to be split update
        limit (int): maximum number of characters in string
        sep (string): the character on which to split
    
    Note:
        A string will automatically be split on a line-break character.
    """
    result = []
    _string = string.split('\n')
    for sub_string in _string:
        words = sub_string.split()
        if max(map(len, words)) > limit:
            raise ValueError("limit is too small")
        part, others = words[0], words[1:]
        for word in others:
            if len(sep) + len(word) > limit - len(part):
                result.append(part)
                part = word
            else:
                part += sep + word
        if part:
            result.append(part)
    return result


def create_table(the_list, column_widths=None, default_width=None):
    """Create lines for a complex reStructured text table.
    
    Args:
        the_list (list): Python dictionaries with the same keys
        column_widths (list): int representing column width in fixed-characters
        default_width (int): common column width in fixed-characters
    """
    if not the_list or not isinstance(the_list, list):
        return ''
    for item in the_list:
        if not isinstance(item, dict):
            return ''
    # setup configuration
    try:
        default = int(default_width)
    except:
        default = DEFAUlT_COL_WIDTH

    settings = []
    headers = the_list[0].keys()
    column_widths = column_widths if column_widths else []
    settings = {}
    for key, header in enumerate(headers):
        settings[header] = column_widths[key] if key < len(column_widths) else default
    # create header as print-ready lines
    lines = []
    lines.append("+")
    lines.append("|")
    lines.append("+")
    for key, val in settings.items():
        lines[1] += key.ljust(val) + '|'
        lines[0] += '-'*val + '+'
        lines[2] += '='*val + '+'
    # set up blocks of text ("multi-line") for each row/col
    formatted = []
    for rec_no, record in enumerate(the_list):
        formatted.append({'max_rows': 1, 'text': {}})
        for key, val in record.items():
            split_text = split_string(string=val, limit=settings[key])
            formatted[rec_no]['text'][key] = split_text
            if len(split_text) > formatted[rec_no]['max_rows']:
                formatted[rec_no]['max_rows'] = len(split_text)
    # create body as print-ready lines
    line_no = 3
    for format_item in formatted:
        rows = format_item['max_rows']
        for row in range(0, rows):
            lines.append("|")
        for col_key, col_text in format_item['text'].items():
            col_size = settings[col_key]
            for row in range(0, rows):
                if len(col_text) <= row:
                    lines[line_no + row] += ' '.ljust(col_size) + '|'
                else:
                    lines[line_no + row] += col_text[row].ljust(col_size) + '|'
        lines.append(lines[0])
        line_no += 1 + rows

    return lines