Rename figure files (figure 3.jpg -> figure 4.jpg)

figure_rename.py

"""Rename a list of figures, making space for a new figure

Ex: Figure 1, Figure 2, Figure 3 -> Figure 1, Figure 3, Figure 4
"""

import sys
import os
import re


def get_file_list():
    """Return a list of files in the current directory"""
    file_list = os.listdir(os.getcwd())
    return file_list


def number_from_name(fname):
    """Return figure number by matching regex to fname"""
    match = re.match(r'figure (\d+)', fname, flags=re.IGNORECASE)
    if match is not None:
        fignum = int(match.group(1))
        return fignum
    else:
        return None


def rename(fname, new_figure_number, diff=1):
    """Rename fname by incrementing its number by diff, only if its number is
    greater than new_figure_number.
    """
    fignum = number_from_name(fname)
    if fignum is not None and fignum >= new_figure_number:
        new_name_string = 'Figure {}'.format(fignum + diff)
        new_fname = re.sub('Figure \d+', new_name_string,
                           fname, flags=re.IGNORECASE)
        os.rename(fname, new_fname)

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print "usage: figure_rename.py n"
        print "where n is the number of the new figure"
        sys.exit()

    file_list = get_file_list()
    file_list.sort(key=number_from_name,)
    try:
        new_figure_number = int(sys.argv[1])
    except ValueError:
        print "n must be an integer"
        sys.exit()
    for fname in reversed(file_list):
        rename(fname, new_figure_number)