python合并多个dict---合并多个字典值---字典值相加

序

主要是借助Counter、函数传参和+运算符重载！各有优劣！

多个dict同key值相加

collection.Counter

借助collections.Counter，但是它只适用于值为整数或者小数类型**，否则报错！**

from collections import Counter
a = {"1":2}
b = {"1":30}
print(dict(Counter(a)+Counter(b)))

a = {"1":2.0}
b = {"1":30.5}
print(dict(Counter(a)+Counter(b)))

传参

借助函数传参，但是不能同值合并。如下：

a = {"1":2}
b = {"2":3}

def merge_dicts(**kwargs):
    return kwargs

merge_dicts(**a, **b)

重载+号

from collections.abc import Iterable

class MyDict:
    def __init__(self, dic):
        self._dic = dic
    
    def __add__(self, other):
        new_dic = self._dic
        for k, v in other._dic.items():
            if k in new_dic:
                if isinstance(v, Iterable) or isinstance(v, int) or isinstance(v, float):
                    new_dic[k] += v
            else:
                new_dic[k] = v
        self._dic = new_dic
        return self._dic
    
a = MyDict({1: "11a"})
b = MyDict({10: 21, 1: "11b"})
a+b

多个dict合并

两种方法

# 方法一, 借助函数传参
a = {"1":2}
b = {"2":3}

def update(**kwargs):
    return kwargs

update(**a, **b)

输出如下：

# 方法二
from collections import Counter
a = {"1":2}
b = {"2":3}
dict(Counter(a)+Counter(b))

练习

请您对以上三种方法的弊端进行复现。