Question

嗨，我正在尝试创建应该如下所示的嵌套字典：

{'4/1': {'A': 5, 'B': 6},  '4/2': {'A': 1, , 'B': 7}, '4/3': {'A': 4, 'B': 3}}

我得到的是：

{'4/1': {'A': 5}, '4/2': {'A': 1}, '4/3': {'A': 4}}

代码：

import random
import datetime as dt

futuresIncome = {}
incomeTypes = ["A", "B"]

for incomeType in incomeTypes:
    for month in range(4, 5):
        for day in range(1, 4):
            date = str(month) + "/" + str(day)
            
            if date in futuresIncome.keys():
                continue
            else:
                futuresIncome[date] = {}
                futuresIncome[date][incomeType] = random.randint(1, 11)

我做错了什么？谢谢。

Answer 1

您需要使用defaultdict：

import random
import datetime as dt
from collections import defaultdict

futuresIncome = defaultdict(dict)
incomeTypes = ["A", "B"]

for incomeType in incomeTypes:
    for month in range(4, 5):
        for day in range(1, 4):
            date = str(month) + "/" + str(day)
            futuresIncome[date][incomeType] = random.randint(1, 11)

Answer 2

您不应该在 continue 块中if，而是添加当前 date 的数据：

if date in futuresIncome.keys():
    futuresIncome[date][incomeType] = random.randint(1, 11)

您还可以使用 setdefault() 方法并摆脱 if-else 块：

for incomeType in incomeTypes:
    for month in range(4, 5):
        for day in range(1, 4):
            date = str(month) + "/" + str(day)
            futuresIncome.setdefault(date, {}).update({incomeType: random.randint(1, 11)})

Answer 3

            if date in futuresIncome.keys():
                continue

这部分导致

            else:
                futuresIncome[date] = {}
                futuresIncome[date][incomeType] = random.randint(1, 11)

如果 futuresIncome 不包含此日期，则只会执行一次。

可能你想做这样的事情：

            if date in futuresIncome.keys():
                futuresIncome[date] = {}
            futuresIncome[date][incomeType] = random.randint(1, 11)

一般来说，比这更好的选择是 defaultdict。

Answer 4

我会建议在最内层循环中迭代incomeTypes，如下所示： `

import random

import datetime as dt

futuresIncome = {}

incomeTypes = ["A", "B"]


for month in range(4, 5):

    for day in range(1, 4):

         for incomeType in incomeTypes:
            date = str(month) + "/" + str(day)
            
            if date in futuresIncome.keys():
                continue
            else:
                futuresIncome[date] = {}
                futuresIncome[date][incomeType] = random.randint(1, 11)`

在 for 循环中创建嵌套字典

4 个答案: