将字典列表分组为Class对象

问题描述

我有4个按键的字典列表

dict_list = [
{'key1': 'a','key2':'b','key3':'p','key4':'q' },{'key1': 'a','key4':'r' },'key2':'c','key2':'d','key4':'q' }
]

我的abc类如下

class abc:
   def __init__(self,val1,val2,val3,val4)
       self.val1 = val1
       self.val2 = val2
       self.val3 = val3
       self.val4 = val4

@classmethod
def from_resultdict(cls,result):
        return cls(result['key1'],result['key2'],result['key3'],result['key4'])

我得到带有以下代码段的列表[abc]

return [abc.from_resultdict(r) for r in dict_list]

我现在想添加一个class2用于根据key1和key2的值对对象列表进行分组

class class2:
      def __init__(self,value1,value2)
          self.value1 = value1
          self.value2 = value2
          self.list_of_abcs: List[abc]

我想为dict_list创建3个class2对象，例如

object1 {
  value1 = a
  value2 = b
  list_of_abcs = [abc_object1,abc_object2]
}

object2 {
 value1 = a
 value2 = c
 list_of_abcs = [abc_object3,abc_object4]
}

object3 {
 value1 = a
 value2 = d
 list_of_abcs = [abc_object5]
}

我该如何实现？

解决方法

让我们暂时忽略这些类；您可以与我们的好朋友collections.defaultdict进行分组：

import collections
from pprint import pprint

dict_list = [
    {'key1': 'a','key2': 'b','key3': 'p','key4': 'q'},{'key1': 'a','key4': 'r'},'key2': 'c','key2': 'd','key4': 'q'}
]

groups = collections.defaultdict(list)
for d in dict_list:
    groups[(d['key1'],d['key2'])].append(d)

pprint(dict(groups))

输出

{('a','b'): [{'key1': 'a','key4': 'r'}],('a','c'): [{'key1': 'a','d'): [{'key1': 'a','key4': 'q'}]}

从那里，您可以根据需要将输出（for group_key,members in groups.items()）包装到类/对象中。

,

为dict对象创建一个Class2，以便为每个Abc对象找到正确的对象。

class Class2:
    def __init__(self,value1,value2)
        self.value1 = value1
        self.value2 = value2
        self.list_of_abcs = []
    
objects = {}

for abc in abc_list:
    key = (abc.val1,abc.val2)
    if key not in objects: # create a Class2 instance if it doesn't exist yet
        objects[key] = Class2(key[0],key[1])
    # append the abc-object to the correct Class2 instance
    objects[key].list_of_abcs.append(abc)