Hierarchical file path in python

Question

The input file contains a list of file paths. suggest an algorithm for sorting the hierarchy as shown below

Enter

A/file1 A/B/C/D/file3 A/B/file1 A/B/file2 A/B/C/D/file1 A/file2 A/W/X/Y/Z/file1 A/W/file1 A/W/X/file1 A/file3 A/B/C/file1 A/W/X/Y/file1 A/B/file2 

Expected Result

 A/file1 A/file2 A/file3 A/B/file1 A/B/file2 A/B/C/file1 A/B/C/D/file1 A/B/C/D/file3 A/W/file1 A/W/X/file1 A/W/X/Y/file1 A/W/X/Y/Z/file1 

tried coding as shown below, the result does not fit as expected

 import sys,os d1,d2 = '','' l1 = [ x for x in open(sys.argv[1])] s2 = sorted(l1,key = lambda x : len(x.split('/'))) for linE in s2: f1 = linE.strip('\n') d1 = os.path.dirname(f1) if d1 != d2 : print d2 = d1 print linE, 

Current output

 A/file1 A/file2 A/file3 A/B/file1 A/B/file2 A/W/file1 A/B/file2 A/W/X/file1 A/B/C/file1 A/B/C/D/file3 A/B/C/D/file1 A/W/X/Y/file1 A/W/X/Y/Z/file1 

please help me with the algorithm do the same

Answer 1

 str = """A/file1 A/B/C/D/file3 A/B/file1 A/B/file2 A/B/C/D/file1 A/file2 A/W/X/Y/Z/file1 A/W/file1 A/W/X/file1 A/file3 A/B/C/file1 A/W/X/Y/file1 A/B/file2""" import string files = string.split(str, "\n") import os.path std = sorted(files, key=lambda file: (os.path.dirname(file), os.path.basename(file))) print std[0] for i in range(1,len(std)): if os.path.dirname(std[i]) != os.path.dirname(std[i-1]): print "" print std[i]