如何去掉 JSON 中多余的花括号？

Question

我基本上是在创建通讯录，我想在 JSON 上存储数据以进行练习。我已经从字典中排序了一个允许它的代码，但问题是当我重新运行脚本时，另一个字典被附加到现有的字典中，创建了几个额外的大括号，引发错误“End of预期文件。

这是代码：

import json


new_contacts = {}


def contacts():
    while True:
        name = input("Contact's name: ")
        email = input("Email: ")
        number = input("Phone number: ")
        new_contacts[name] = {"email": email, "number": number}
        
        """cursor.execute(
            'INSERT INTO contacts VALUES (?, ?, ?)',
            (name, email, number)
            )"""
        restart_or_not = input("Continue? y/n ").lower()

        if restart_or_not == "y":
            print(new_contacts)
            continue
        else:
            with open('contact_book.json', 'a') as file:
                json.dump(new_contacts, file, indent=4)
            break


contacts()

这是从中得出的 JSON 的样本：

{
    "d": {
        "email": "e",
        "number": "3"
    },
    "h": {
        "email": "y",
        "number": "6"
    },
    "f": {
        "email": "r",
        "number": "3"
    },
    "n": {
        "email": "j",
        "number": "9"
    }
}{
    "g": {
        "email": "j",
        "number": "0"
    }
}

前四个条目不会造成任何问题，因为它们附加在同一个运行中，但如果我退出程序并重新运行它（例如“g”），那么新字典造成冲突。有什么建议吗？

Answer 1

这样做的一种方法是，在添加到文件之前，删除最后一个右括号 } 并在转储之前，将字典转换为字符串并使用此 [=12 删除第一个括号=].

我为您编写的另一种方法是将 json 加载到变量中，添加新输入，然后将其重新转储到文件中

import json

from os import path # it helps to check if file exists


new_contacts = {}

def contacts():
    while True:
        name = input("Contact's name: ")
        email = input("Email: ")
        number = input("Phone number: ")
        new_contacts[name] = {"email": email, "number": number}
        
        """cursor.execute(
            'INSERT INTO contacts VALUES (?, ?, ?)',
            (name, email, number)
            )"""
        restart_or_not = input("Continue? y/n ").lower()

        if restart_or_not == "y":
            print(new_contacts)
            continue
        else:
            # if the file doesn't exist, write an empty json object into it
            # which will make it easier later to load data from
            if not path.exists('contact_book.json'):
                with open('contact_book.json', 'w+') as file:
                    json.dump({}, file)
            # This loads the data into the variable dict called loaded_data
            with open('contact_book.json', 'r') as file:
                loaded_data = json.load(file)
                for k, v in new_contacts.items():
                    loaded_data[k] = v
            # redumps your data into the json file
            with open('contact_book.json', 'w') as file:
                json.dump(loaded_data, file, indent=4)
            break

contacts()

Answer 2

刚刚更新了您代码的其他部分。它检查 文件是否存在 。如果存在，则读取并更新文件的内容，然后将其转储到文件中。如果它不存在，您的旧代码将被执行。

if os.stat("contact_book.json").st_size != 0:
    with open('contact_book.json', 'r+') as file:
        contents = json.loads(file.read())
        contents.update(new_contacts)
        file.seek(0)
        json.dump(contents, file, indent=4)
else:
        with open('contact_book.json', 'a') as file:
        json.dump(new_contacts, file, indent=4)
        break

老实说，这不是一个有效的解决方案。不过这个应该可以引出点子。

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