new_contents: '''
  f = open('d1.txt')
  for line in f:
      print line
  f.close
  '''
  
  '''
  with open('d1.txt') as f:
      for line in f:
          print line
  f.close
  '''
  
  '''
  filename = raw_input(">>> ")
  #file = filename + '.txt'
  #print file.read()
  with open(filename + '.txt') as f:
  	for line in f:
  		print line
  f.close()
  '''
  import os
  filename = raw_input(">>> ")
  fi= filename + '.txt'
  print os.path.exists(fi)
  #print file.read()
  with open(fi) as f:
  	for line in f:
  		print line
  f.close()
  
  
subject: 测试 for in 按行读取文件