如何在不替换新密钥的情况下保留 JSON 中的第一个密钥？

Question

Main.py

import json

def test(key, value):
    with open("test.json", "r", encoding="utf-8") as f:
        x = json.load(f)

        num = 1

        try:
            if f"q{num}" in x["keys"]: # Checking if index 1 is exist
                for _ in range(num):
                    num += 1
        except:
            pass

        x["keys"] = {}
        x["keys"][f"{num}"] = {"key": key, "value": value} # Dict for json file
        
        with open("test.json", "w", encoding="utf-8") as f:
            json.dump(x, f, indent=4, ensure_ascii=False) # Write the json file


test("test", "testvalue")
test("test2", "testvalue2")

test.json

{
    "keys": {
        "1": {
            "key": "test2",
            "value": "testvalue2"
        }
    }
}

如何保留第一个问题而不替换第二个问题？我想这样做（如果可能的话）：

{
    "keys": {
        "1": {
            "key": "test",
            "value": "testvalue"
        },

        "2": {
            "key": "test2",
            "value": "testvalue2"
        }
    }
}

我不确定是否真的可以做到这一点。如果无法做到这一点，请告诉我！

Answer 1

你可以尝试这样的事情。它检查您是否真的可以将文件加载为 json（因为加载空文件会失败），然后在 keys 字典中找到最大键值并添加一个带有递增键的新条目。

import json

def test(key, value):
    with open("test.json", "r", encoding="utf-8") as f:
        try:
            x = json.load(f)
            next_key = max(map(int, x['keys'].keys())) + 1
        except:
            # empty file
            x = { 'keys' : {} }
            next_key = 1
    
    # add the new value
    x['keys'].update({ next_key : { 'key' : key, 'value' : value } })
    
    # write the new data
    with open("test.json", "w", encoding="utf-8") as f:
        json.dump(x, f, indent=4, ensure_ascii=False)

运行之后 test.json 的内容：

test("test", "testvalue")
test("test2", "testvalue2")

将是：

{
    "keys": {
        "1": {
            "key": "test",
            "value": "testvalue"
        },
        "2": {
            "key": "test2",
            "value": "testvalue2"
        }
    }
}

如何在不替换新密钥的情况下保留 JSON 中的第一个密钥？

How can I keep the first key in the JSON without replacing the new one?

python

json

python-3.x