如何对Python dict的5个随机样本进行price值求和聚合？

你遇到的问题是因为random.sample(mydict.items(), 5)返回的是元组列表，每个元素都是(键, 包含name和price的子字典)，直接用sum()去加这些元组肯定会报错——Python没法把元组当成数值来求和。

修复方案1：直接处理采样后的元组列表 #

修改求和的代码，遍历每个采样到的元组，提取子字典里的price值再求和：

import random

mydict = {
    1: {"name":"item1","price": 16}, 
    2: {"name":"item2","price": 14},
    3: {"name":"item3","price": 16}, 
    4: {"name":"item4","price": 14}, 
    5: {"name":"item5","price": 13},
    6: {"name":"item6","price": 16},
    7: {"name":"item7","price": 11}, 
    8: {"name":"item8","price": 12}, 
    9: {"name":"item9","price": 14},
    10: {"name":"item10","price": 14},
}

randomlist = random.sample(mydict.items(), 5)
# 提取每个元组中子字典的price值求和
print(sum(item[1]['price'] for item in randomlist))

修复方案2：直接采样字典的值（更简洁） #

如果不需要原字典的键，直接采样mydict.values()（也就是所有子字典），再提取price求和，代码更清爽：

import random

mydict = {
    1: {"name":"item1","price": 16}, 
    2: {"name":"item2","price": 14},
    3: {"name":"item3","price": 16}, 
    4: {"name":"item4","price": 14}, 
    5: {"name":"item5","price": 13},
    6: {"name":"item6","price": 16},
    7: {"name":"item7","price": 11}, 
    8: {"name":"item8","price": 12}, 
    9: {"name":"item9","price": 14},
    10: {"name":"item10","price": 14},
}

# 直接采样子字典列表
random_values = random.sample(mydict.values(), 5)
print(sum(v['price'] for v in random_values))

两种方案都能正确计算5个随机条目的price总和，选哪种看你是否需要保留原字典的键。

内容的提问来源于stack exchange，提问作者NIPPE