python json & pickle 模块

Posted 2020-10-10

用于序列化的两个模块

• json，用于字符串 和 python数据类型间进行转换
• pickle，用于python特有的类型 和 python的数据类型间进行转换

Json模块提供了四个功能：dumps、dump、loads、load

pickle模块提供了四个功能：dumps、dump、loads、load

"""
python 3 JSON模块使用
"""

import json
data = {
    "北京市": {
        "朝阳区": ["三里屯", "望京", "国贸"],
        "海淀区": ["五道口", "学院路", "后厂村"],
        "东城区": ["东直门", "崇文门", "王府井"],
    },
    "上海市": {
        "静安区": [],
        "黄浦区": [],
        "虹口区": [],
    }
}

1、json.dumps    dict-->strting

s_dumps = json.dumps(data, sort_keys=True, indent=4, ensure_ascii=False)
print(type(s_dumps))
print(s_dumps)

output：
<class ‘str‘>
{
    "上海市": {
        "虹口区": [],
        "静安区": [],
        "黄浦区": []
    },
    "北京市": {
        "东城区": [
            "东直门",
            "崇文门",
            "王府井"
        ],
        "朝阳区": [
            "三里屯",
            "望京",
            "国贸"
        ],
        "海淀区": [
            "五道口",
            "学院路",
            "后厂村"
        ]
    }
}

2、json.loads  string-->dict

r_loads = json.loads(s_dumps)
print(type(r_loads))
print(r_loads)

output：
<class ‘dict‘>
{‘上海市‘: {‘虹口区‘: [], ‘静安区‘: [], ‘黄浦区‘: []}, ‘北京市‘: {‘东城区‘: [‘东直门‘, ‘崇文门‘, ‘王府井‘], ‘朝阳区‘: [‘三里屯‘, ‘望京‘, ‘国贸‘], ‘海淀区‘: [‘五道口‘, ‘学院路‘, ‘后厂村‘]}}

3、json.dump  写入文件

with open("data.json", "w", encoding="UTF-8") as f_dump:
    s_dump = json.dump(data, f_dump, indent=4, ensure_ascii=False)

4、json.load  从文件读取

with open("data.json", "r", encoding="utf-8") as f_load:
    r_load = json.load(f_load)

print(type(r_load))
print(r_load)

output：
<class ‘dict‘>
{‘北京市‘: {‘朝阳区‘: [‘三里屯‘, ‘望京‘, ‘国贸‘], ‘海淀区‘: [‘五道口‘, ‘学院路‘, ‘后厂村‘], ‘东城区‘: [‘东直门‘, ‘崇文门‘, ‘王府井‘]}, ‘上海市‘: {‘静安区‘: [], ‘黄浦区‘: [], ‘虹口区‘: []}}