Python json 解析器允许重复键

However, since Python dictionaries don't allow for duplicate keys (and you simply can't change that), you can return the pairs unchanged in the hook and get a nested list of (key, value) pairs when you decode your JSON:

from json import JSONDecoder

def parse_object_pairs(pairs):
    return pairs


data = """
{"foo": {"baz": 42}, "foo": 7}
"""

decoder = JSONDecoder(object_pairs_hook=parse_object_pairs)
obj = decoder.decode(data)
print obj

输出:

[(u'foo', [(u'baz', 42)]), (u'foo', 7)]

如何使用此数据结构取决于您.如上所述，Python 字典不允许重复键，并且没有办法解决这个问题.您甚至会如何根据键进行查找?dct[key] 会模棱两可.

How you use this data structure is up to you. As stated above, Python dictionaries won't allow for duplicate keys, and there's no way around that. How would you even do a lookup based on a key? dct[key] would be ambiguous.

因此，您可以实现自己的逻辑以按照您期望的方式处理查找，或者实现某种避免冲突以使键唯一(如果它们不是唯一的)，然后然后创建嵌套列表中的字典.

So you can either implement your own logic to handle a lookup the way you expect it to work, or implement some sort of collision avoidance to make keys unique if they're not, and then create a dictionary from your nested list.

编辑:既然您说要修改重复键以使其唯一，那么您可以这样做:

Edit: Since you said you would like to modify the duplicate key to make it unique, here's how you'd do that:

from collections import OrderedDict
from json import JSONDecoder


def make_unique(key, dct):
    counter = 0
    unique_key = key

    while unique_key in dct:
        counter += 1
        unique_key = '{}_{}'.format(key, counter)
    return unique_key


def parse_object_pairs(pairs):
    dct = OrderedDict()
    for key, value in pairs:
        if key in dct:
            key = make_unique(key, dct)
        dct[key] = value

    return dct


data = """
{"foo": {"baz": 42, "baz": 77}, "foo": 7, "foo": 23}
"""

decoder = JSONDecoder(object_pairs_hook=parse_object_pairs)
obj = decoder.decode(data)
print obj

输出:

OrderedDict([(u'foo', OrderedDict([(u'baz', 42), ('baz_1', 77)])), ('foo_1', 7), ('foo_2', 23)])

make_unique 函数负责返回一个无冲突的密钥.在这个例子中，它只是用 _n 作为键的后缀，其中 n 是一个增量计数器 - 只需根据您的需要调整它即可.

The make_unique function is responsible for returning a collision-free key. In this example it just suffixes the key with _n where n is an incremental counter - just adapt it to your needs.

因为 object_pairs_hook 完全按照它们在 JSON 文档中出现的顺序接收对，所以也可以通过使用 OrderedDict 来保留该顺序，我将其包含为好吧.

Because the object_pairs_hook receives the pairs exactly in the order they appear in the JSON document, it's also possible to preserve that order by using an OrderedDict, I included that as well.

这篇关于Python json 解析器允许重复键的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持html5模板网！