python字典的增删改查,字典转json

一:python字典的增删改查

1、添加:加入键和值,即可新增,以下是新增了"f":"12ab"

dict = {
    "a": "bbb",
    "b": None,
    "c": True,
    "d": 13,
    "e": ["13", "14"]
}

dict["f"] = "12ab"       # 字典的新增
print(dict)

执行代码结果:

D:\Python36\python.exe D:/test/mingtest/case/bolg/test_19.py
{'a': 'bbb', 'b': None, 'c': True, 'd': 13, 'e': ['13', '14'], 'f': '12ab'}

Process finished with exit code 0

2、删除:可直接使用del方法,删除键,所对应的值也会删除

dict = {
    "a": "bbb",
    "b": None,
    "c": True,
    "d": 13,
    "e": ["13", "14"]
}

del(dict["a"])    #   删除"a": "bbb"
print(dict)

执行代码结果:

D:\Python36\python.exe D:/test/mingtest/case/bolg/test_19.py
{'b': None, 'c': True, 'd': 13, 'e': ['13', '14']}

Process finished with exit code 0

3、修改:键不变,值改变

dict = {
    "a": "bbb",
    "b": None,
    "c": True,
    "d": 13,
    "e": ["13", "14"]
}

dict["a"] = "fffff"      # 修改"a"
print(dict)

执行代码结果:

D:\Python36\python.exe D:/test/mingtest/case/bolg/test_19.py
{'a': 'fffff', 'b': None, 'c': True, 'd': 13, 'e': ['13', '14']}

Process finished with exit code 0

4、查找:

dict = {
    "a": "bbb",
    "b": None,
    "c": True,
    "d": 13,
    "e": ["13", "14"]
}

print(dict["b"])  #  直接print打印对应的键

执行代码结果:

D:\Python36\python.exe D:/test/mingtest/case/bolg/test_19.py
None

Process finished with exit code 0

二:字典转json,json转字典

1、字典转json:看注释

import json         # 导入json这个库
dict = {
    "a": "bbb",
    "b": None,
    "c": True,
    "d": 13,
    "e": ["13", "14"]
}


print(type(dict))       # 打印dict数据什么数据类型?结果显示为python字典
js = json.dumps(dict)   # 使用dumps这个方法对字典转换为json格式
print(js)
print(type(js))         # 打印js的数据类型,属于字符串,说明转换成功,None显示为null,True显示为小写

执行代码结果:

D:\Python36\python.exe D:/test/mingtest/case/bolg/test_19.py

{"a": "bbb", "b": null, "c": true, "d": 13, "e": ["13", "14"]}


Process finished with exit code 0

2、json转字典:看注释

import json         # 导入json这个库
dict = {
    "a": "bbb",
    "b": None,
    "c": True,
    "d": 13,
    "e": ["13", "14"]
}


print(type(dict))       # 打印dict数据什么数据类型?结果显示为python字典
js = json.dumps(dict)   # 使用dumps这个方法对字典转换为json格式
print(js)
print(type(js))         # 打印js的数据类型,属于字符串,说明转换成功,None显示为null,True显示为小写

dict1 = json.loads(js)  # 使用loads这个方法对json转换成字典
print(dict1)            # 打印dict1,运行结果,null显示为None,true显示为大写
print(type(dict1))      # 打印结果显示dict1显示为字典数据类型

执行代码结果:

D:\Python36\python.exe D:/test/mingtest/case/bolg/test_19.py

{"a": "bbb", "b": null, "c": true, "d": 13, "e": ["13", "14"]}

{'a': 'bbb', 'b': None, 'c': True, 'd': 13, 'e': ['13', '14']}


Process finished with exit code 0

 

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