python实现读取大文件并逐行写入另外一个文件

<pre name="code" class="python">creazy.txt文件有4G，逐行读取其内容并写入monday.txt文件里。 

def creazyRead(): 
  ''''' 
  with open("e:creazy.txt","r") as cr: 
    for line in cr: 
      print line 
  ''' 
  ms = open("e:creazy.txt") 
  for line in ms: 
    with open("e:monday.txt","a") as mon: 
      mon.write(line) 

def creazyRead(): 
  ms = open("e:creazy.txt") 
  for line in ms.readlines(): 
    with open("e:monday.txt","a") as mon: 
      mon.write(line)