pickle模块

#!/usr/bin/env python
#coding:utf-8
import pickle
#增加
def create():
        users={'fujinzhou':'123456','pc':'123','wd':'111'}
        f=open('userlist.txt','wb')     #pickle模块是以二进制形式存储在文件中，所以必须用二进制方式打开
        pickle.dump(users,f)            #将字典写入文件
        f.close()
#删除
def delete():
        content={}
        f=open('userlist.txt')          #导入字典的时候不能用wb模式
        content=pickle.load(f)          #将文件导入字典中
        f.close
        content.pop('wd')
        f=open('userlist.txt','wb')     #修改后的字典再次写入文件
        pickle.dump(content,f)
        f.close()

#改
def modify():
        content={}
        f=open('userlist.txt')
        content=pickle.load(f)
        f.close
        content['pc']='666'
        f=open('userlist.txt','wb')
        pickle.dump(content,f)
        f.close()


#查所有
def select():
        content={}
        f=open('userlist.txt')
        content=pickle.load(f)
        f.close()
        print content
        for k,v in content.items():
                print '用户信息:%s-->%s'%(k,v)


#查一条
def selectone(username):
        name=username
        content={}
        userinfo={}
        f=open('userlist.txt')
        content=pickle.load(f)
        f.close()
        userinfo[name]=content[name]
        print userinfo
        return userinfo


create()
delete()
modify()
select()
selectone('pc')

[root@测试虚拟机 fujinzhou]# python pickle_file.py 
{'pc': '666', 'fujinzhou': '123456'}
用户信息:pc-->666
用户信息:fujinzhou-->123456
{'pc': '666'}