在python中从平面列表创建嵌套字典的通用方式 [英] Generic way to create nested dictionary from flat list in python

问题描述

我正在寻找最简单的通用方式来转换此python列表：

I am looking for the simplest generic way to convert this python list:

x = [
        {"foo":"A", "bar":"R", "baz":"X"},
        {"foo":"A", "bar":"R", "baz":"Y"},
        {"foo":"B", "bar":"S", "baz":"X"},
        {"foo":"A", "bar":"S", "baz":"Y"},
        {"foo":"C", "bar":"R", "baz":"Y"},
    ]

into：

foos = [ 
         {"foo":"A", "bars":[
                               {"bar":"R", "bazs":[ {"baz":"X"},{"baz":"Y"} ] },
                               {"bar":"S", "bazs":[ {"baz":"Y"} ] },
                            ]
         },
         {"foo":"B", "bars":[
                               {"bar":"S", "bazs":[ {"baz":"X"} ] },
                            ]
         },
         {"foo":"C", "bars":[
                               {"bar":"R", "bazs":[ {"baz":"Y"} ] },
                            ]
         },
      ]

组合foo，bar ，baz是唯一的，你可以看到列表不一定由这个键排序。

The combination "foo","bar","baz" is unique, and as you can see the list is not necessarily ordered by this key.

推荐答案

#!/usr/bin/env python3
from itertools import groupby
from pprint import pprint

x = [
        {"foo":"A", "bar":"R", "baz":"X"},
        {"foo":"A", "bar":"R", "baz":"Y"},
        {"foo":"B", "bar":"S", "baz":"X"},
        {"foo":"A", "bar":"S", "baz":"Y"},
        {"foo":"C", "bar":"R", "baz":"Y"},
    ]


def fun(x, l):
    ks = ['foo', 'bar', 'baz']
    kn = ks[l]
    kk = lambda i:i[kn]
    for k,g in groupby(sorted(x, key=kk), key=kk):
        kg = [dict((k,v) for k,v in i.items() if k!=kn) for i in g]
        d = {}
        d[kn] = k
        if l<len(ks)-1:
            d[ks[l+1]+'s'] = list(fun(kg, l+1))
        yield d

pprint(list(fun(x, 0)))

---

---

[{'bars': [{'bar': 'R', 'bazs': [{'baz': 'X'}, {'baz': 'Y'}]},
           {'bar': 'S', 'bazs': [{'baz': 'Y'}]}],
  'foo': 'A'},
 {'bars': [{'bar': 'S', 'bazs': [{'baz': 'X'}]}], 'foo': 'B'},
 {'bars': [{'bar': 'R', 'bazs': [{'baz': 'Y'}]}], 'foo': 'C'}]

---

注意：无序！但它与你的一样。

---

note: dict is unordered! but it's the same as yours.

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