序列化 把对象打散成二进制字节 bytes, 方便对象的存储和传输
python中存在三种序列化方案: pikle , shelve, json
1. pickle 把一个对象转化成bytes写入到文件
pickle.dumps() 把对象转换成bytes
import pickle
class Cat:
def __init__(self, name, color):
self.name = name
self.color = color
def chi(self):
print("%s猫会吃老鼠" % self.name)
c = Cat("汪峰","黑色")
bs = pickle.dumps(c) # 把一个对象转化成bytes
print(bs)
pickle.loads() 把bytes转化成对象
cc = pickle.loads(bs) # 把⼆进制反序列化成我们的对象
print(cc)
pickle.dump() 把对象转换成bytes. 写入到文件
c1 = Cat("汪峰1","黑色")
c2 = Cat("汪峰2","黑色")
c3 = Cat("汪峰3","黑色")
lst = [c1, c2, c3]
f = open("cat.dat", mode="ab")
pickle.dump(lst, f) # 把对象写到文件中
pickle.load() 把文件中的bytes读取. 转化成对象
f = open("cat.dat", mode="rb")
lst = pickle.load(f) # 从文件中读取第一次
for cc in lst:
cc.chi()
记住一点: pikle序列化的内容是二进制内容(bytes), 不是给人看的
2. shelve 小型数据库, 当作dict使用
shelve提供python的持久化操作, 即把数据写在硬盘上
import shelve
d = shelve.open("sylar") # 文件类型的字典
d['wf'] = "汪峰"
d.close()
d = shelve.open("sylar")
print(d['wf'])
d.close()
d = shelve.open("sylar") # 文件类型的字典
d['wf'] = {"name": "汪峰", "age": 18, "wife": {"name": "章子怡", "hobby": "拍电影"}}
d.close()
d = shelve.open("sylar", writeback=True) # 文件类型的字典 wirteback把修改的内容自动的回写到文件中
d['wf']['wife']['hobby'] = "当导师" # 不能直接修改， 需要writeback配合
d.close()
d = shelve.open("sylar")
for k, v in d.items():
print(k, v) # wf {'name': '汪峰', 'age': 18, 'wife': {'name': '章子怡', 'hobby': '当导师'}}
print(type(d)) #<class 'shelve.DbfilenameShelf'>
3. json 以前用xml 先在用json
json.dumps() 把字典转换成json字符串
json.loads() 把json字符串转化成字典
json.dump() 把字典转换成json字符串. 写入到文件
json.load() 把文件中的json字符串读取. 转化成字典
ensure_ascii = False 可以处理中文
mport json
# 准备一个字典
dic = {"a": "小萝莉", "b": "大萝莉", "c": "猥琐大叔", "d": False, "e": None}
# python中可以直接把字典或者列表转化成json
s = json.dumps(dic, ensure_ascii=False) # pickle
print(type(s)) # str
print(s) # {"a": "小萝莉", "b": "大萝莉", "c": "猥琐大叔", "d": false, "e": null} json的打印结果和python有区别
s = '{"a": "小萝莉", "b": "大萝莉", "c": "猥琐大叔", "d": false, "e": null}'
d = json.loads(s) # 把json转化成字典
print(d) # {'a': '小萝莉', 'b': '大萝莉', 'c': '猥琐大叔', 'd': False, 'e': None}
print(type(d)) # dict
#
dic = {"a": "小萝莉", "b": "大萝莉", "c": "猥琐大叔", "d": False, "e": None, "wf":{"name":"半壁江山", "hobby":"皮裤"}}
f = open("sylar.json", mode="w", encoding="utf-8")
json.dump(dic, f, ensure_ascii=False, indent=4) # 4个空格 = 1个tab
f = open("sylar.json", mode="r", encoding="utf-8")
d = json.load(f) #
print(d)
default = 把对象转化成字典. 需要自己写转换过程
object_hook = 把字典转化成对象. 需要自己写转换过程
class Person:
def __init__(self, firstName, lastName):
self.firstName = firstName
self.lastName = lastName
s = '{"firstName": "尼古拉斯", "lastName": "刘能"}'
def func(dic):
return Person(dic['firstName'], dic["lastName"])
p = json.loads(s, object_hook=func) # 通过函数func把字典转换回对象
print(p.firstName, p.lastName) #尼古拉斯 刘能
p = Person("尼古拉斯", "刘能")
# 把对象转换成json
s = json.dumps(p.__dict__, ensure_ascii=False) # 方案一, 转的是字典
def func(obj):
return {
"firstName": obj.firstName,
"lastName": obj.lastName
}
s = json.dumps(p, default=func, ensure_ascii=False) # 方案二 转化的也是字典
print(s) #{"firstName": "尼古拉斯", "lastName": "刘能"}
f = open("movie.json", mode="r", encoding="utf-8")
dic1 = json.load(f) # 当json文件中保存多个json的时候不能一次性全部都读取出来
print(dic1)
f = open("movie.json", mode="r", encoding="utf-8")
for line in f:
line = line.strip()
if line == "": # 如果是空字符跳过
continue
else:
d = json.loads(line) # 一行一行的处理
print(d)
4. configparser 处理windows配置文件的 dict
import configparser
config = configparser.ConfigParser() # 创建对象
config['DEFAULT'] = { # 特殊
"name":"腾讯qq木马",
"time":"qq更新时间",
"version":"1.0"
}
config['SERVER_1'] = {
"IP":"192.168.1.123",
"port":"12306"
}
config['SERVER_2'] = {
"IP":"192.168.1.178",
"port":"12311"
}
config['SERVER_3'] = {
"IP":"192.168.1.176",
"port":"12312"
}
# 写入到文件
config.write(open("qq.ini", mode="w", encoding="utf-8"))
# 读取内容
config = configparser.ConfigParser()
# 读取内容
config.read("qq.ini", encoding="utf-8") # 此时我们把文件中的内容读取到config
print(config['SERVER_1']['IP']) # 字典
print(config['SERVER_2']['name'])
print(config.get("SERVER_3", "IP")) # 字典
for k, v in config['DEFAULT'].items():
print(k, v)