day22 Python json模块

import json

dic = {"k1": "v1", "k2": "v2", "k3": None, "k4": False, "k5": {"name": "fhb", "age": "18"}}


# 将字典转换为json字符串
jd = json.dumps(dic, ensure_ascii=False)
print(jd)
print(type(jd))


# 将json字符串还原为dict
jl = json.loads(jd)
print(jl)
print(type(jl))


# 将json字符串写入文件
with open("fhb.json", mode="w", encoding="utf-8") as f1:
    json.dump(dic, f1, ensure_ascii=False, indent=4)
    """
    ensure_ascii: 数据不转换为ascii，中文存储的时候保持中文存储
    indent: 保存文件之后数据格式化json的时候缩进等于4
    """


# 从文件读取json字符串
with open("fhb.json", mode="r", encoding="utf-8") as f2:
    obj = json.load(f2)
    print("obj -->", obj)
    print("type(obj) -->", type(obj))


# 将对象存到json字符串中
class Car(object):

    def __init__(self, name ,price):
        self.name = name
        self.price = price


c = Car("benz",1000)

# 方法一
p = json.dumps(c.__dict__, ensure_ascii=False)
print(p) # {"name": "benz", "price": 1000}
 
# 方法二
def func(obj):
    
    return {
        "name": obj.name,
        "price": obj.price,
    }

p = json.dumps(c, default=func)
print(p) # {"name": "benz", "price": 1000}



# 将json还原成对象
s = '{"name": "benz", "price": 1000}'

def func1(dict):
    return Car(dict["name"],dict["price"])

p = json.loads(s ,object_hook=func1)

print(p.name,p.price) # benz 1000