Python自动化开发从浅入深-语言基础(pickle)

　　pickle可以将对象以文件的形式保存到磁盘上，称之为对象序列化，pickle.dump(obj, file[, protocol])是对象序列化的格式，它将obj序列化结果数据流写入到file文件对象中。

参数protocol是序列化模式，默认值为0，表示以文本的形式序列化。protocol的值还可以是1或2，表示以二进制的形式序列化,1是老式的二进制协议；2是2.3版本引入的新二进制协议，较以前的更高效。其中协议0和1兼容老版本的python。

　　pickle.load(file)称为反序列化对象。从磁盘中读取文件，将文件中的数据解析为一个Python对象。

import pickle

class Person:
  def __init__(self,name,age):
      self.name=name
      self.age=age
  def show(self,stat):
      if stat == 1:
          print ("Write To File:
Name is %s,Age is %s"%(self.name,str(self.age)))
      elif stat == 2:
          print ("Raed From File:
Name is %s,Age is %s"%(self.name,str(self.age)))

value1 = Person("zhaohong", 56)
value2 = Person("zhaomeng", 30)
value3 = Person("liuming", 51)
value1.show(1)
value2.show(1)
value3.show(1)
with open('d:/account.txt','wb') as fp:
    pickle.dump(value1,fp,0)
    pickle.dump(value2,fp,0)
    pickle.dump(value3,fp,0)

with open('d:\account.txt','rb') as fp:
    a1 =pickle.load(fp)
    a2 =pickle.load(fp)
    a3 =pickle.load(fp)

a1.show(2)
a2.show(2)
a3.show(2)

运行结果

Write To File:
Name is zhaohong,Age is 56
Write To File:
Name is zhaomeng,Age is 30
Write To File:
Name is liuming,Age is 51
Raed From File:
Name is zhaohong,Age is 56
Raed From File:
Name is zhaomeng,Age is 30
Raed From File:
Name is liuming,Age is 51

  磁盘文件

 利用pickle进行序列化时，切记需要clear_memo()，不然python不会进行多次序列化。