rename and modify tags of audios of harry potter to play in Android phone in order

gistfile1.txt

# This script renames Harry Potter audio file names to play on Android in order

import os
import re
import eyed3

def sub_func1(m):
    strm = m.group()
    digit_len = len(strm)-1
    prefix = ''
    k = 0
    while k < 4 - digit_len:
        prefix += '0'
        k += 1
    return prefix + strm

def sub_func2(m):
    strm = m.group()
    digit_len = len(strm)-1
    prefix = ''
    k = 0
    while k < 4 - digit_len:
        prefix += '0'
        k += 1
    return '-' + prefix + strm[1:]

def hp_rename(folder):
    file_list = os.listdir(folder)

    #complete digits
    for f in file_list:

        path = os.path.join(folder,f)
        if os.path.isdir(path):
            continue

        f1 = re.sub(r'^\d+', '', f)

        p = re.compile(r'(\d+-)')
        f2 = p.sub(sub_func1, f1)

        p = re.compile(r'(-\d+)')
        f3 = p.sub(sub_func2, f2)

        old_file_path = folder + '\\' + f
        new_file_path = folder + '\\' + f3

        #Set the tags of mp3 files
        meta = eyed3.load(new_file_path)
        meta.tag._setTitle(f3[0:-4].decode('utf-8'))
        meta.tag.save()

        if f is not f3:
            os.rename(old_file_path, new_file_path)



if __name__ == '__main__':
    hp_rename("C:\\tmp\\harry potter\\hp3")
    #hp_rename("C:\\tmp\\justing")