Python物件轉換為json
Python中內建了json庫,用起來超級方便,json現在以成為開發的必備。
json的api有下面4個:
json.loads() 將json轉換為dict json.dumps() 將dict轉換為json json.load() 將json檔案轉換為dict json.dump() 將dict轉換為json檔案 person.json
注意:dict也可以是類物件
dict轉換為json
import json person = { 'name': 'jack', 'age': 15, 'email': '[email protected]' } print('dict:', person) person_json = json.dumps(person) # 轉換為json print('json:', person_json)
輸出:
dict: {'name': 'jack', 'age': 15, 'email': '[email protected]'} json: {"name": "jack", "age": 15, "email": "[email protected]"}
json轉換為dict
import json person_dict = json.loads('{"name": "jack", "age": 15, "email": "[email protected]"}') print('person dict:', person_dict)
輸出:
person dict: {'name': 'jack', 'age': 15, 'email': '[email protected]'}
類物件轉換為json
import json class Person: def __init__(self, name, age, email): self.name = name self.age = age self.email = email person = Person('tom', 38, '[email protected]') person_json = json.dumps(person.__dict__) print('person json:', person_json)
輸出:
person json: {"name": "tom", "age": 38, "email": "[email protected]"}
json.dumps()
不能直接傳遞一個物件例項否則回報TypeError: Object of type Person is not JSON serializable
錯誤
為了避免這個錯誤,我們需要修改:
import json class Person: def __init__(self, name, age, email): self.name = name self.age = age self.email = email # 將person轉換為dict def convert2json(person): return { 'name': person.name, 'age': person.age, 'email': person.email } person = Person('tom', 38, '[email protected]') # 第二個引數傳遞轉換函式,或者使用default=lambda o: o.__dict__ person_json = json.dumps(person, default=convert2json) print('person json:', person_json)
json轉換為類物件
import json class Person: def __init__(self, name, age, email): self.name = name self.age = age self.email = email def convert2json(dict_json): return Person(dict_json['name'], dict_json['age'], dict_json['email']) person = json.loads('{"name": "tom", "age": 38, "email": "[email protected]"}', object_hook=convert2json) print('person:', person)
輸出:
person: <__main__.Person object at 0x10a7230b8>
loads函式只能將json轉換為字典,需要我們自己轉換為物件。
dict/物件轉換為json檔案
import person = {"name": "tom", "age": 38, "email": "[email protected]"} with open('person.json', 'w') as f: json.dump(person, f)
當前目錄下會多一個person.json檔案,內容是:
{"name": "tom", "age": 38, "email": "[email protected]"}
將json檔案轉換為dict/物件
import json with open('person.json', 'r') as f: print(json.load(f))
輸出:
{'name': 'tom', 'age': 38, 'email': '[email protected]'}