问题

我有一个包含字符串:字符串键值对的json文件。

我尝试首先使用json.load加载文件，然后更新字典，但是当我将更新后的字典转储时，我丢失了键。无法弄清楚如何更新值。

我正在尝试将**sampleID**的值更新为其他内容并写回同一文件。

```python
{"key":"{\"url\":\"DEFAULT\",\"id\":\"tzz22s6a\",\"sampleID\":\"jahsdioadhao\",\"isPassRequired\":false,\"isKeyRequired\":true,\"materialType\":\"SATIN\",\"clothType\":\"DEFAULT\"}"}

到目前为止，我尝试了以下方法，它可以更新sampleId的值，但是文件的格式已经改变，并且我丢失了键，即**"key"**。

with open(os.path.join(root, file_name)) as jsonFile:
    d = json.load(jsonFile)
    for values in d:
        data = json.loads(d[values])
        data['sampleID'] = 'newValue'

with open(os.path.join(root, file_name), 'w') as jsonFile:
    json.dump(data, jsonFile, indent=4)

<details>
<summary>英文:</summary>

I have a json file consisting of a dict of String:String

I tried to first load the file using json.load and then update the dict but when I dump the updated dict I lose the key. Unable to figure out how to update a value.

I&#39;m trying to update the value of **sampleID** to something else and write back to the same file.

{"key":"{"url":"DEFAULT","id":"tzz22s6a","sampleID":"jahsdioadhao","isPassRequired":false,"isKeyRequired":true,"materialType":"SATIN","clothType":"DEFAULT"}"}

what I tried so far, which updates the value of sampleId but the format of the file is changed and also I loose the key i.e., **"key"**

with open(os.path.join(root, file_name)) as jsonFile:
d = json.load(jsonFile)
for values in d:
data = json.loads(d[values])
data['sampleID'] = 'newValue'

with open(os.path.join(root, file_name), 'w') as jsonFile:
json.dump(data, jsonFile, indent=4)

</details>


# 答案1
**得分**: 1

需要将`data`转换回字符串，并将其插入回原始字典中。

```python
with open(os.path.join(root, file_name)) as jsonFile:
    d = json.load(jsonFile)
    for k in d:
        data = json.loads(d[k])
        data['sampleID'] = 'newValue'
        d[k] = json.dumps(data)

with open(os.path.join(root, file_name), 'w') as jsonFile:
    json.dump(d, jsonFile, indent=4)

输出

{"key": "{\"url\": \"DEFAULT\", \"id\": \"tzz22s6a\", \"sampleID\": \"newValue\", \"isPassRequired\": false, \"isKeyRequired\": true, \"materialType\": \"SATIN\", \"clothType\": \"DEFAULT\"}"}

如果您不真正需要以这种格式保存`json`，将`d[k] = json.dumps(data)` 替换为 `d[k] = data` 也会给您一个有效的 `json`。

with open(os.path.join(root, file_name)) as jsonFile:
    d = json.load(jsonFile)
    for k in d:
        data = json.loads(d[k])
        data['sampleID'] = 'newValue'
        d[k] = json.dumps(data)

with open(os.path.join(root, file_name), 'w') as jsonFile:
    json.dump(d, jsonFile, indent=4)

{"key": "{\"url\": \"DEFAULT\", \"id\": \"tzz22s6a\", \"sampleID\": \"newValue\", \"isPassRequired\": false, \"isKeyRequired\": true, \"materialType\": \"SATIN\", \"clothType\": \"DEFAULT\"}"}

答案2

得分: 1

看起来你提供的示例 JSON 中，嵌套的 JSON 对象没有正确序列化。

要更新嵌套键，你应该在 d 对象内部进行修改，或者将 key 重新赋值为更新后的 data JSON 对象，如下所示：

with open(os.path.join(root, file_name)) as jsonFile:
    d = json.load(jsonFile)
    for key in d:
        # 如果输入的 JSON 是有效的，你不需要在下面的行再次加载它，但在你的示例中它是无效的。
        data = json.loads(d[key])
        data['sampleID'] = 'newValue'
        # 将 "key" 在 d 中设置为更新后的数据字典。
        d[key] = data

附加说明：

• d 的迭代器将循环遍历键，所以我将其更改为 for key in d 以使其更清晰。
• 你粘贴的示例中的嵌套 JSON 由于反斜杠字符而不是有效的 JSON，所以为了复制你的代码，我做了以下更改：

import json
import re

data = {"key": "{\"url\":\"DEFAULT\",\"id\":\"tzz22s6a\",\"sampleID\":\"jahsdioadhao\",\"isPassRequired\":false,\"isKeyRequired\":true,\"materialType\":\"SATIN\",\"clothType\":\"DEFAULT\"}"}

# 创建正则表达式编译器
pattern = re.compile(r"\\\"")

# 将模式中的字符替换为空字符串 `""`，并在 data["key"] 上进行替换
pattern.sub("", data["key"])

# 将 data["key"] 直接设置为 JSON 字符串的字典。
data["key"] = json.loads(data["key"])

# 替换 "key" 中的 "sampleID" 值
data["key"]["sampleID"] = "newValue"

# 这将产生以下结果：
{"key": {"url": "DEFAULT", "id": "tzz22s6a", "sampleID": "newValue", "isPassRequired": false, "isKeyRequired": true, "materialType": "SATIN", "clothType": "DEFAULT"}}

希望这对你有所帮助。

with open(os.path.join(root, file_name)) as jsonFile:
    d = json.load(jsonFile)
    for key in d:
        # You shouldn't need to load this again on the line below if the input json is valid but in your example it is not.
        data = json.loads(d[key])
        data['sampleID'] = 'newValue'
        # Set "key" in d to be the updated data dict.
        d[key] = data

import json
import re

data = {"key":"{\"url\":\"DEFAULT\",\"id\":\"tzz22s6a\",\"sampleID\":\"jahsdioadhao\",\"isPassRequired\":false,\"isKeyRequired\":true,\"materialType\":\"SATIN\",\"clothType\":\"DEFAULT\"}"}

# Create a regex compiler
pattern = re.compile(r"\\")

# Sub the characters in pattern with empty string `""` in place on data["key"]
pattern.sub("", data["key"])

# Set data["key"] in place to be the dict of the json string.
data["key"] = json.loads(data["key"])

# Replace the value of "sampleID" in "key"
data["key"]["sampleID"] = "newValue"

# which produces
{'key': {'url': 'DEFAULT',
  'id': 'tzz22s6a',
  'sampleID': 'newValue',
  'isPassRequired': False,
  'isKeyRequired': True,
  'materialType': 'SATIN',
  'clothType': 'DEFAULT'}}