python 学习 rfind find

yangfeng@yangfeng-desktop:~$ cat python.py 

#!/usr/bin/env python

absfile=r"root/log/ls/"

index1=absfile.find("/")

print index1

index2=absfile.rfind("/")

print index2

yangfeng@yangfeng-desktop:~$ ./python.py 

4

11

find()----找到的第一个符合字符的index

rfind()-----找到最后一个符合的字符的index

import operator, os, sys

def get_file_size(path):

  st = os.lstat(path)

  return st.st_size;

def main(argv):

  output = []

  roots = argv[1:]

  for root in roots:

    base = len(root[:root.rfind(os.path.sep)])

    for dir, dirs, files in os.walk(root):

      relative = dir[base:]

      for f in files:

        try:

          row = (

              get_file_size(os.path.sep.join((dir, f))),

              os.path.sep.join((relative, f)),

            )

          output.append(row)

        except os.error:

          pass

  output.sort(key=operator.itemgetter(0), reverse=True)

  for row in output:

    print "%12d  %s" % row

if __name__ == '__main__':

  main(sys.argv)