Create nested dictionary in a for loops

Question

Hi I'm trying to create nested dictionary which is supposed to look like:

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

What I'm getting is:

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

Code:

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)

What am I doing wrong? Thank you.

In your outer loop, you add a key for each date for "A", then on the next iteration (B) you then check if the key is there (which it is) and then continue, so your second iteration doesn't do anything. Try use pdb to debug this, you'll see that you always hit the continue path once you get to the B iteration. — Dan
– Dan, Commented Apr 7, 2021 at 13:47
also, instead of futuresIncome[date] = {}, consider using a defaultdict(dict) instead. And you can change date = str(month) + "/" + str(day) to date = f"{month}/{day}" — Dan
– Dan, Commented Apr 7, 2021 at 13:48

Nikita Zhuikov · Accepted Answer · 2021-04-07 13:48:37Z

2

You need to use 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)

answered Apr 7, 2021 at 13:48

Nikita Zhuikov

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Comments

Krishna Chaurasia · Accepted Answer · 2021-04-07 14:18:21Z

1

You should not continue in the if block but add the data for the current date:

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

You could also make use of the setdefault() method and get rid of the if-else block:

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)})

edited Apr 7, 2021 at 14:18

answered Apr 7, 2021 at 13:47

Krishna Chaurasia

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Comments

Sienki · Accepted Answer · 2021-04-07 13:51:37Z

0

            if date in futuresIncome.keys():
                continue

This part causes that

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

will be executed only once if futuresIncome doesn't contain this date.

Probably you wanted to do something like that:

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

Generally, better option than that would be defaultdict.

answered Apr 7, 2021 at 13:51

Sienki

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Comments

Krishna Chaurasia · Accepted Answer · 2021-04-07 14:20:18Z

0

I will suggest iterating through incomeTypes in the innermost loop as shown below: `

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)`

edited Apr 7, 2021 at 14:20

Krishna Chaurasia

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answered Apr 7, 2021 at 13:52

Niru

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