Attempt

lss.py

import re
import itertools
import sys
from collections import Counter
from os import listdir
from os.path import isfile, join

filelist = []
fileset = set()
parse_number = lambda num: "%%0%sd" % len(num)

class LSS:
    def __init__(self, location="."):
        self.location = location
        self.__process_filenames()

    def __normalize_filename(self, filename):
        return { "name": filename, "group": re.sub(r'\d+', '(\d+)', filename)}

    def __process_filenames(self):
        file_list = sorted(
            [
                self.__normalize_filename(f) for f in listdir(self.location)
                if isfile(join(self.location, f))
            ],
            key=lambda x: x['name'])

        groups = itertools.groupby(file_list, lambda x: x['group'])
        self.__process_groups(groups)

    def __process_groups(self, groups):
        for name, files in groups:
            name = files.next()
            fileNumbers = [
                re.match(file['group'], file['name']).groups() for file in list(files)
            ]
            if fileNumbers:
                filelist.append({
                    "file": name.get("name"),
                    "group": name.get("group"),
                    "tuple": fileNumbers,
                    "digits": re.findall('\d+', name.get("name")),
                    "tuple_count": Counter(item[0] for item in fileNumbers),
                    "count": len(fileNumbers)
                })
            else:
                filelist.append({"file": name.get("name"), "count": 1})
        self.__process_occurrences(filelist)

    def __process_occurrences(self, filelist):
        for entry in filelist:
            if entry.get("group"):
                filename = entry.get("group")
                fileconcat = entry.get("tuple")
                for numbervalue, occurrences in entry.get("tuple_count").items():
                    if len(numbervalue) is 1:
                        format_number = lambda num: "%%0%sd" % len(num)

                    filename = entry.get("group")
                    digits = entry.get("digits")

                    for count, number_padding in enumerate(digits):
                        formated_file_name = re.sub(r'\(\\d.\)', numbervalue, filename, count=1)
                        final_name = re.sub(r'\(\\d.\)', number_padding, formated_file_name, count=1)
                    fileset.add((int(occurrences), final_name))
            else:
                filename = entry.get("file")
                fileset.add((entry.get("count"), filename))

        for count, filename in sorted(fileset, reverse=False, key=lambda tup: tup[1]):
            print "%d %s" % (count, filename)

if __name__ == '__main__':
    if len(sys.argv) > 1:
        LSS(sys.argv[1])
    else:
        LSS()