File Sorting by Integer

filesort.py

import os

subDir = os.listdir(dirname)
#remove .DS_Store in mac osx
subDir = filter (lambda a: a != '.DS_Store', subDir)

#files name are Testing1.txt , Testing2.txt, Testing3.txt
toreplace = "Testing"

#x[0:len(toreplace)-1] is Testing
#int(x[len(toreplace):-4]) for 1, 2, 3,4,etc is integer value
#x[-4:] .txt

subDir = sorted(subDir, key=lambda x: (x[0:len(toreplace)-1],int(x[len(toreplace):-4]),x[-4:]))        

for subname in subDir:
    print subname