过滤 dict 的 dict [英] Filter a dict of dict

问题描述

我是 Python 新手，我不确定使用 dict 的 dict 是个好主意，但这是我的问题.我有一个 dict 的 dict，我想通过内部 dict 的键进行过滤:

a ={ 'key1' : {'id1' :[0,1,2] , 'id2' :[0,1,2], 'id3' :[4,5,6]}'key2' : {'id3' :[0,1,2] , 'id4' :[0,1,2]}'key3' : {'id3' :[0,1,2] , 'id1' :[4,5,6]}}

例如，我想通过id1"过滤:

result = { 'key1' : {'id1' :[0,1,2] }'key3' : {'id1' :[4,5,6]}}

我通过获取所有值尝试了过滤方法:

r = [('key1' ,{'id1' :[0,1,2] , 'id2' :[0,1,2], 'id3' :[4,5,6]})('key3' , {'id3' :[0,1,2] , 'id1' :[4,5,6]})]

此外，过滤器方法返回一个列表，我想将格式保留为字典.

提前致谢

解决方案

试试这个:

<预><代码>>>>{ k: v['id1'] for k,v in a.items() if 'id1' in v }{'key3': [4, 5, 6], 'key1': [0, 1, 2]}

对于 Python 2.x，您可能更喜欢使用 iteritems() 而不是 items() 并且您仍然需要一个相当新的 Python(我认为是 2.7)对于字典理解:对于较旧的 python 使用:

dict((k, v['id1']) for k,v in a.iteritems() if 'id1' in v )

如果你想提取多个值，那么我认为你最好完整地写出循环:

def 查询(数据，想要):结果 = {}对于 k, v 在 data.items():v2 = { k2:v[k2] for k2 in want if k2 in v }如果 v2:结果[k] = v2返回结果

给予:

<预><代码>>>>查询(一，('id1'，'id2')){'key3': {'id1': [4, 5, 6]}, 'key1': {'id2': [0, 1, 2], 'id1': [0, 1, 2]}}

I new in Python and I am not sure it is a good idea to use dict of dict but here is my question. I have a dict of dict and I want to filter by the key of the inside dict:

a ={ 'key1' : {'id1' :[0,1,2] , 'id2' :[0,1,2], 'id3' :[4,5,6]}
     'key2' : {'id3' :[0,1,2] , 'id4' :[0,1,2]}
     'key3' : {'id3' :[0,1,2] , 'id1' :[4,5,6]}
   }

For exemple , I want to filter by 'id1' to have :

result = { 'key1' : {'id1' :[0,1,2] }
           'key3' : {'id1' :[4,5,6]}
         }

I have tried the filter method by I get all the value:

r = [('key1' ,{'id1' :[0,1,2] , 'id2' :[0,1,2], 'id3' :[4,5,6]})
     ('key3' , {'id3' :[0,1,2] , 'id1' :[4,5,6]})
   ]

Furthermore the filter method returns a list and I want to keep the format as a dict.

Thanks in advance

解决方案

Try this:

>>> { k: v['id1'] for k,v in a.items() if 'id1' in v }
{'key3': [4, 5, 6], 'key1': [0, 1, 2]}

For Python 2.x you might prefer to use iteritems() instead of items() and you'll still need a pretty recent python (2.7 I think) for a dictionary comprehension: for older pythons use:

dict((k, v['id1']) for k,v in a.iteritems() if 'id1' in v )

If you want to extract multiple values then I think you are best to just write the loops out in full:

def query(data, wanted):
    result = {}
    for k, v in data.items():
        v2 = { k2:v[k2] for k2 in wanted if k2 in v }
        if v2:
            result[k] = v2
    return result

giving:

>>> query(a, ('id1', 'id2'))
{'key3': {'id1': [4, 5, 6]}, 'key1': {'id2': [0, 1, 2], 'id1': [0, 1, 2]}}

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