python将每个单词按空格分开并保存到文件中

# -*- coding: utf-8 -*-
'''
python读取英文文件，将每个单词按照空格分开，并将每个单词独自放一行
'''
def dcfenhang(infile,outfile):

  infopen = open(infile,'r',encoding='utf-8')
  outopen = open(outfile,'w',encoding='utf-8')
  lines = infopen.readlines()
  for line in lines:
    for db in line.split():
      if db not in outfile:
        outopen.write(db+'\n')
  infopen.close()
  outopen.close()
dcfenhang("jb51.txt","fenci.txt")