Python 如何向简单JSON文件添加key:value对

JSON

{
    "user1": "password1",
    "user2": "password2"
}

代码

假设我有一个新用户user3，我将把他的密码和用户名存储到两个不同的变量中

username = "user3"
password = "password3"

输出目标

我希望我的JSON文件最终看起来像这样：

{
    "user1": "password1",
    "user2": "password2",
    "user3": "password3
}

---

只需将json解析为dict，添加键/值对并将其转储回json字符串：

import json

j = '''{
    "user1": "password1",
    "user2": "password2"
}'''

username = "user3"
password = "password3"

my_dict = json.loads(j)
my_dict[username] = password

json.dumps(my_dict)
# '{"user1": "password1", "user2": "password2", "user3": "password3"}'

如果您从一个文件开始，它基本上是相同的-只需打开该文件并使用

load（）

和

dump（）

。比如：

import json

path = "/path/to/file.txt"
outpath = "/path/to/output_file.txt"

username = "user3"
password = "password3"

with open(path) as json_file:
    my_dict = json.load(json_file)

my_dict[username] = password

with open(outpath, 'w') as json_file:
    json.dump(my_dict, json_file)

---

只需将json解析为dict，添加键/值对并将其转储回json字符串：

import json

j = '''{
    "user1": "password1",
    "user2": "password2"
}'''

username = "user3"
password = "password3"

my_dict = json.loads(j)
my_dict[username] = password

json.dumps(my_dict)
# '{"user1": "password1", "user2": "password2", "user3": "password3"}'

如果您从一个文件开始，它基本上是相同的-只需打开该文件并使用

load（）

和

dump（）

。比如：

import json

path = "/path/to/file.txt"
outpath = "/path/to/output_file.txt"

username = "user3"
password = "password3"

with open(path) as json_file:
    my_dict = json.load(json_file)

my_dict[username] = password

with open(outpath, 'w') as json_file:
    json.dump(my_dict, json_file)