CODEWITHSUNDEEP
python
MGA
MGA

Reputation: 325

How to add new dictionaries to an existing Key in a dictionary python

I have this predefined dicitonary : 

customMappingDict = {'Validated' : '',
                 'notValidated' : ''}

I want to add new dictionaries(!?) if possible to the existing key as its value, as in : 

customMappingDict = {'Validated' : 'Key: 'Value', Key1: 'Value'',
                 'notValidated' : 'Key: 'Value', Key1: 'Value''}

For the resulting dictionary I would like to call upon the two preexisting keys(Validated and notValidated) and cycle the keys from its value(!?) as so :

for key in customMappingDict['Validated'].keys():
    pass

...

Output should be : 

key, key1

What I've tried :

if condition:
    str1 = '{}'.format(provLst[0])
    customMappingDict['Validated']: dict[str1]= '{}'.format(provLst[1])
else:
    str2 = '{}'.format(provLst[0])
    customMappingDict['notValidated']: dict[str2] = '{}'.format(provLst[1])

The worning that i'm getting in PyCharm : 

Class 'type' does not define '__getitem__', so the '[]' operator cannot be used on its instances

Upvotes: 2

Views: 93

Answers (2)

Nitheesh MN
Nitheesh MN

Reputation: 628

Try this

Suppose i have a dict

d = {'red': 100, 'green': 1000}

Now I want to change the value of 'red' to a dict

d['red'] = dict()
d['red']['light_red'] = 100.10
d['red']['dark_red'] = 100.20

Now will be

{'red': {'light_red': 100.10, 'dark_red': 100.20}, 'green': 1000}

Upvotes: 0

Anwarvic
Anwarvic

Reputation: 12992

Using collections.defaultdict will save you a lot of the headache. The idea of defaultdict is to create a dictionary that has a default value. In this case, the default value will be a dictionary as well.

You can do that simply like so:

from collections import defaultdict


customMappingDict = defaultdict(dict)
if condition:
    str1 = '{}'.format(provLst[0])
    customMappingDict['Validated'][str1] = f'{provLst[1]}'
else:
    str2 = '{}'.format(provLst[0])
    customMappingDict['notValidated'][str2] = f'{provLst[1]}'

SideNote: f{provLst[0]} is the same as '{}'.format(provLst[0]) just cleaner !!

Upvotes: 2

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