Python3-笔记-E-008-库-字典序列化shelve

Posted 2020-10-12

import shelve
# shelve_demo.py 持久性字典:Python对象的持久化
# 键值对形式, 将内存数据通过文件持久化, 值支持任何pickle支持的Python数据格式
# 与pickle的主要区别是键值对方式, 并且在目录下生成三个文件
class Person(object):
    def __init__(self):
        self.name = "luzhuo"
        self.age = 21

    def __str__(self):
        return "name: {}, age: {}".format(self.name, self.age)

path = "shelve_demo.txt"


def shelve_write():
    ‘‘‘
    序列化
    ‘‘‘

    with shelve.open(path) as write: # 打开
        write["nums"] = [1, 2, 3, 4, 5]  # 写
        write["obj"] = Person()


def shelve_read():
    ‘‘‘
    反序列化
    ‘‘‘

    with shelve.open(path) as read:  # 打开
        nums = read.get("nums")  # 读取
        print(nums)
        clazz = read["obj"]
        print(clazz)

        del read["obj"]  # 删除
        print("obj" in read)

        keys = list(read.keys())  # 所有key
        print(keys)


shelve_write()
shelve_read()