Count occurrences of file basenames from a single folder and select those that appear once ...

basename_counter.py

from os import listdir
from os.path import basename, isfile, join, splitext

src_dir = 'c:\\repository\\'
files = {}

for file in listdir(src_dir):
    src_file = join(src_dir, file)
    if isfile(src_file):
        base = splitext(basename(src_file))[0]
        if base in files:
            files[base] += 1
        else:
            files[base] = 1

unique = [file for file in files.keys() if files[file] == 1]
print unique