为什么在使用json.dumps时python dict的int键变成字符串？

Question

根据此转换表，使用JSON模块进行序列化时，Python int会以JSON数字的形式写入-正如我所期望和期望的那样。

我有一本带有整数键和整数值的字典：

>>> d = {1:2}

>>> type(d.items()[0][0])

<type 'int'>

>>> type(d.items()[0][1])

<type 'int'>

当我使用json模块将其序列化为JSON字符串时，该值被写为数字，但密钥被写为字符串：

>>> json.dumps(d)

'{"1": 2}'

这不是我想要的行为，它似乎特别损坏，因为它使json.dumps / json.loads往返中断了：

>>> d == json.loads(json.dumps(d))

False

为什么会发生这种情况，有没有办法我可以强制将密钥写为数字？

Answer 1

原因很简单，JSON不允许整数键。object&nbsp; &nbsp; {}&nbsp; &nbsp; { members }&nbsp;members&nbsp; &nbsp; pair&nbsp; &nbsp; pair , memberspair&nbsp; &nbsp; string : value&nbsp; # Keys *must* be strings.关于如何解决此限制-您首先需要确保接收实现可以处理技术上无效的JSON。然后，您可以替换所有的引号或使用自定义的序列化程序。

Answer 2

如果可能，此函数将递归地将所有字符串键转换为int键。如果不可能，则密钥类型将保持不变。我在下面稍微调整了JLT的示例。使用我的一些巨大的嵌套字典，这些代码使字典的大小发生了变化，但有一个例外。无论如何，归功于JLT！def pythonify(json_data):&nbsp; &nbsp; correctedDict = {}&nbsp; &nbsp; for key, value in json_data.items():&nbsp; &nbsp; &nbsp; &nbsp; if isinstance(value, list):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value = [pythonify(item) if isinstance(item, dict) else item for item in value]&nbsp; &nbsp; &nbsp; &nbsp; elif isinstance(value, dict):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value = pythonify(value)&nbsp; &nbsp; &nbsp; &nbsp; try:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; key = int(key)&nbsp; &nbsp; &nbsp; &nbsp; except Exception as ex:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp; &nbsp; &nbsp; &nbsp; correctedDict[key] = value&nbsp; &nbsp; return correctedDict

Answer 3

如果确实需要，可以使用以下命令检查是否可以再次将其转换为整数的键：def pythonify(json_data):&nbsp; &nbsp; for key, value in json_data.iteritems():&nbsp; &nbsp; &nbsp; &nbsp; if isinstance(value, list):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value = [ pythonify(item) if isinstance(item, dict) else item for item in value ]&nbsp; &nbsp; &nbsp; &nbsp; elif isinstance(value, dict):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; value = pythonify(value)&nbsp; &nbsp; &nbsp; &nbsp; try:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; newkey = int(key)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; del json_data[key]&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; key = newkey&nbsp; &nbsp; &nbsp; &nbsp; except TypeError:&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; pass&nbsp; &nbsp; &nbsp; &nbsp; json_data[key] = value&nbsp; &nbsp; return json_data