csv2tbl.py

#!/usr/bin/env python
# file: csv2tbl.py
# vim:fileencoding=utf-8:ft=python
#
# Copyright © 2012-2018 R.F. Smith <rsmith@xs4all.nl>.
# SPDX-License-Identifier: MIT
# Created: 2012-06-17T19:25:53+02:00
# Last modified: 2019-09-16T21:54:30+0200
"""Convert a CSV file to a LaTeX table."""

from collections import Counter
from datetime import date
import os.path
import sys

__version__ = "2019.09.16"


def main(argv):
    """
    Entry point for csv2tbl.

    Arguments:
        argv: Command line arguments.
    """
    binary = os.path.basename(argv[0])
    if len(argv) < 2:
        print(f"{binary} ver. {__version__}")
        print(f"Usage: {binary} file", file=sys.stderr)
        sys.exit(0)
    # Read the data into a list of lines.
    lines = readlines(argv[1])
    # Check which seperator is used.
    sep = csvsep(lines)
    # Get the filename and remove the extension.
    fname = os.path.basename(argv[1])
    if fname.endswith((".csv", ".CSV")):
        fname = fname[:-4]
    # Create a format definition for the tabular environment.
    columns = len(lines[1].split(sep))
    columns = "l" * columns
    # Print the output.
    print("% Generated from " + str(argv[1]))
    print("% by csv2tbl.py on " + str(date.today()))
    print(r"\begin{table}[!htbp]")
    print(r"  \centering")
    print(r"  \caption{\label{tb:" + fname + r"}" + fname + r"}")
    print(r"  \begin{tabular}{" + columns + r"}")
    print(r"    \toprule")
    fmtcsv(lines[0], sep)
    print(r"    \midrule")
    for l in lines[1:]:
        fmtcsv(l, sep)
    print(r"    \bottomrule")
    print(r"  \end{tabular}")
    print(r"\end{table}")


def readlines(filename):
    """
    Read a file and return the contents as a list of lines.

    Arguments:
        filename name of the file to read

    Returns:
        A list of stripped lines.
    """
    with open(filename) as infile:
        lines = infile.readlines()
    return [l.strip() for l in lines]


def csvsep(lines, separators=",\t;:"):
    """
    Determine the separator used in the lines of csv data.

    Arguments:
        lines: CSV data as a list of strings.
        separator: String of separators.

    Returns:
        The most occuring separator character.
    """
    letters, sep = Counter(), Counter()
    for ln in lines:
        letters.update(ln)
    for s in ",\t;:":
        sep[s] = letters[s]
    return sep.most_common()[0][0]


def fmtcsv(line, sep):
    """
    Format a single line of CSV data as a LaTeX table cells.

    Arguments:
        line: The string of CSV data to convert
        sep: The separator to use.
    """
    # Skip empty lines.
    if len(line) == line.count(sep):
        return
    if line.endswith(sep):
        line = line[: -len(sep)]
    # Escape existing ampersands.
    line = line.replace(r"&", r"\&")
    outs = "    " + line.replace(sep, r" & ") + r"\\"
    print(outs)


if __name__ == "__main__":
    main(sys.argv)