从 Json Dict/Python 中删除密钥

Question

我刚开始写这个脚本来练习，它会接受输入，然后把它写在 Json 文件中。 代码如下所示：

import json


command = int(input("Do You Want To Add, Or Remove From List? 1/2 "))
if command == 1:
    add_key = input("Type In key Name: ")
    add_val1 = input("Type In Value N1: ")
    add_val2 = input("Type In Value N2: ")

    with open('jjj.json', 'r+') as jjson:
        tvsh = json.load(jjson)
        new_tvsh = {add_key: [add_val1, add_val2]}
        tvsh.update(new_tvsh)
        jjson.seek(0)
        json.dump(tvsh, jjson)
elif command == 2:
    with open('jjj.json', 'r+') as jjson:
        tvsh = json.load(jjson)
        chooseremove = input("Choose Key To Remove: ")
        try:
            del tvsh[chooseremove]
        except KeyError as ex:
            print(f"No such key: {chooseremove} ")
        jjson.seek(0)
        json.dump(tvsh, jjson)

Json 文件如下所示：

{"Key1":["Val1","Val2"],"Key2":["Val1","Val2"],"Key3":["Val1","Val2"]}

但是当我尝试删除密钥（例如 key3）时，我的 json 文件将是这样的：

{"Key1":["Val1","Val2"],"Key2":["Val1","Val2"]} "Key3":["Val1","Val2"]}

它在 dict 之外取键，但在末尾添加“}”任何想法我能做什么？

编辑：也试过 .pop 但结果相同

Answer 1

这里的错误是运行jjson.seek(0)后跟json.dump(tvsh, jjson)不会破坏现有文件的内容，只会覆盖它。 由于您在删除Key3后写入 JSON 文件的数据结构较小，因此不会覆盖整个文件（即， "Key3":["Val1","Val2"]}是您第一次写入时遗留的）。

这里的解决方案是运行jjson.truncate()运行后json.dump(tvsh, jjson)

以下程序显示了差异，不依赖于用户输入：

#!/usr/bin/env python3

import json

# Test data
initial_data = {
    "Key1":["Val1", "Val2"],
    "Key2":["Val1", "Val2"],
    "Key3":["Val1", "Val2"],
}
final_data = {
    "Key1":["Val1", "Val2"],
    "Key2":["Val1", "Val2"],
}

with open('testA.json', 'w') as f:
    json.dump(initial_data, f)
    f.seek(0)
    json.dump(final_data, f)

with open('testB.json', 'w') as f:
    json.dump(initial_data, f)
    f.seek(0)
    json.dump(final_data, f)
    f.truncate()