Python 操作 JSON 的 9 个示例
Json&＃xff08;Javascript Object Notation 的缩写&＃xff09;是一种数据交换格式&＃xff0c;最常用于客户端-服务器通信&＃xff1b;当然你也可以将它保存到本地&＃xff0c;所以也可以用来作为配置文件&＃xff1b;Json 很像 Python 中的字典&＃xff0c;下面就让我们来一起学习如何用 Python 来操作 Json
01 将字典转化为 JSON
输入&＃xff1a;
data &＃61; {"key1":"value1","key2":"value2"}
输出&＃xff1a;
data &＃61; {"key1":"value1","key2":"value2"}
有什么不一样吗&＃xff1f;其实它们是很相似的
示例代码&＃xff1a;
import jsondata &＃61; {"key1" : "value1", "key2" : "value2"}# 我们用到了json库的dumps方法&＃xff0c;将Python对象转化为Json对象
jsonData &＃61; json.dumps(data)
print(jsonData)
02 访问 JSON 中的key2的值
输入&＃xff1a;
data &＃61; {"key1":"value1","key2":"value2"}
输出&＃xff1a;
value2
示例代码&＃xff1a;
import jsonsampleJson &＃61; """{"key1": "value1", "key2": "value2"}"""# 我们用到了json库的loads方法
data &＃61; json.loads(sampleJson)
print(data[&＃39;key2&＃39;])
03 将 Json 格式化后输出
输入&＃xff1a;
sampleJson &＃61; {"key1": "value1", "key2": "value2"}
输出&＃xff1a;
{"key1" &＃61; "value2","key2" &＃61; "value2","key3" &＃61; "value3"
}
示例代码&＃xff1a;
import jsonsampleJson &＃61; {"key1" : "value2", "key2" : "value2", "key3" : "value3"}
prettyPrintedJson &＃61; json.dumps(sampleJson, indent&＃61;2, separators&＃61;(",", " &＃61; "))
print(prettyPrintedJson)
04 将 Json 按key排序后保存输出到文件中
输入&＃xff1a;
sampleJson &＃61; {"id" : 1, "name" : "value2", "age" : 29}
输出&＃xff1a;
{"age": 29,"id": 1,"name": "value2"
}
示例代码&＃xff1a;
import jsonsampleJson &＃61; {"id" : 1, "name" : "value2", "age" : 29}print("Started writing JSON data into a file")
with open("sampleJson.json", "w") as write_file:json.dump(sampleJson, write_file, indent&＃61;4, sort_keys&＃61;True)
print("Done writing JSON data into a file")
05 访问 Json 的嵌套对象&＃xff0c;并输出 salary的值
输入&＃xff1a;
sampleJson &＃61; """{"company":{"employee":{"name":"emma","payble":{"salary":7000,"bonus":800}}}
}"""
输出&＃xff1a;
7000
示例代码&＃xff1a;
import jsonsampleJson &＃61; """{"company":{"employee":{"name":"emma","payble":{"salary":7000,"bonus":800}}}
}"""data &＃61; json.loads(sampleJson)
print(data[&＃39;company&＃39;][&＃39;employee&＃39;][&＃39;payble&＃39;][&＃39;salary&＃39;])
06 将类对象转化为 Json
输入&＃xff1a;
class Vehicle:def __init__(self, name, engine, price):self.name &＃61; nameself.engine &＃61; engineself.price &＃61; pricevehicle &＃61; Vehicle("Toyota Rav4", "2.5L", 32000)
输出&＃xff1a;
{"name": "Toyota Rav4","engine": "2.5L","price": 32000
}
示例代码&＃xff1a;
import json
from json import JSONEncoderclass Vehicle:def __init__(self, name, engine, price):self.name &＃61; nameself.engine &＃61; engineself.price &＃61; priceclass VehicleEncoder(JSONEncoder):def default(self, o):return o.__dict__vehicle &＃61; Vehicle("Toyota Rav4", "2.5L", 32000)print("Encode Vehicle Object into JSON")
vehicleJson &＃61; json.dumps(vehicle, indent&＃61;4, cls&＃61;VehicleEncoder)
print(vehicleJson)
07 将 Json 转化为类对象
输入&＃xff1a;
{ "name": "Toyota Rav4", "engine": "2.5L", "price": 32000 }
输出&＃xff1a;
vehicleObj.name, vehicleObj.engine, vehicleObj.price
示例代码&＃xff1a;
import jsonclass Vehicle:def __init__(self, name, engine, price):self.name &＃61; nameself.engine &＃61; engineself.price &＃61; pricedef vehicleDecoder(obj):return Vehicle(obj[&＃39;name&＃39;], obj[&＃39;engine&＃39;], obj[&＃39;price&＃39;])vehicleObj &＃61; json.loads(&＃39;{ "name": "Toyota Rav4", "engine": "2.5L", "price": 32000 }&＃39;,object_hook&＃61;vehicleDecoder)print("Type of decoded object from JSON Data")
print(type(vehicleObj))
print("Vehicle Details")
print(vehicleObj.name, vehicleObj.engine, vehicleObj.price)
08 判断 Json 格式是否正确
输入&＃xff1a;
{"company":{"employee":{"name":"emma","payble":{"salary":7000"bonus":800}}}
}
输出&＃xff1a;
Given JSON string is Valid False
即格式错误
示例代码&＃xff1a;
import jsondef validateJSON(jsonData):try:json.loads(jsonData)except ValueError as err:return Falsereturn TrueInvalidJsonData &＃61; """{ "company":{ "employee":{ "name":"emma", "payble":{ "salary":7000 "bonus":800} } } }"""
isValid &＃61; validateJSON(InvalidJsonData)print("Given JSON string is Valid", isValid)
09 获取 JSON 中key为name的所有值
输入&＃xff1a;
[{"id":1,"name":"name1","color":["red","green"]},{"id":2,"name":"name2","color":["pink","yellow"]}
]
输出&＃xff1a;
示例代码&＃xff1a;
import jsonsampleJson &＃61; """[{"id":1,"name":"name1","color":["red","green"]},{"id":2,"name":"name2","color":["pink","yellow"]}
]"""data &＃61; []
try:data &＃61; json.loads(sampleJson)
except Exception as e:print(e)dataList &＃61; [item.get(&＃39;name&＃39;) for item in data]
print(dataList)
今天的教程&＃xff0c;主要学习了&＃xff1a;如何使用Python操作Json&＃xff0c;包括读取和写入&＃xff1b;大家都学会了吗&＃xff1f;
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