python_文本文件里面随机抽取若干行，写入新的文本文件里面

天一直阴沉沉的，真想早点下班啊。。。。。。

 

 1 #encoding=utf-8

 2 import random

 3 from sets import Set

 4    

 5 def copyfile(srcfile, dstfile, linenum):

 6      """

 7          get linenum different lines out from srcfile at random

 8          and write them into dstfile

 9      """

10      result = []

11      ret = False

12      try:

13          srcfd = open(srcfile,'r')

14      except IOError:

15          print 'srcfile doesnot exist!'

16          return ret

17      try:

18          dstfd = open(dstfile,'w')

19      except IOError:

20          print 'dstfile doesnot exist!'

21          return ret

22      srclines = srcfd.readlines()

23      srclen = len(srclines)

24      while len(Set(result)) < int(linenum):

25          s = random.randint(0,srclen-1)

26          result.append(srclines[s])

27      for content in Set(result):

28          dstfd.write(content)

29      srcfd.close()

30      dstfd.close()

31      ret = True

32      return ret

33   

34 if __name__ == "__main__":

35      srcpath = raw_input('input srcfile path')

36      dstpath = raw_input('input dstfile path')

37      linenum = raw_input('input linenum')

38      print copyfile(srcpath,dstpath,linenum)

 

 hadoop快点跑吧。。。。。。