Remove all keys excepts those mentioned from a dict python3

Question

i have a nested python dictionary where i am trying to remove all keys except those mentioned. I found a solution here where we can remove keys specified, what i am trying to do is reverse of it, i want to remove all keys except those mentioned. So i made a slight change in the function, but i am getting an empty dict.

from collections import MutableMapping


def remove_fields(d, list_of_keys_to_remove):
    if not isinstance(d, (dict, list)):
        return d
    if isinstance(d, list):
        return [v for v in (remove_fields(v, list_of_keys_to_remove) for v in d) if v]
    return {k: v for k, v in ((k, remove_fields(v, list_of_keys_to_remove)) for k, v in d.items()) if
            k in list_of_keys_to_remove}

Adding sample input EDIT: let suppose i want to keep RENEWAL_TYPE

{
  'G_1': [
    {
      'ACCOUNTING_RULE_ID': '1',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'RENEW'
    },
    {
      'ACCOUNTING_RULE_ID': '2',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'RENEW'
    },
    {
      'ACCOUNTING_RULE_ID': '3',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'DO_NOT_RENEW'
    },
    {
     'ACCOUNTING_RULE_ID': '4',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'RENEW'
    }
  ]
}

Jim Nilsson · Answer 1 · 2019-08-26T11:55:46.080

You're looking for the intersection between the set of keys in the dict and the set of values in the list. i.e. all keys that exist in both sets.

Try this:

from collections import MutableMapping


d = { 'A': 1, 'B': 2, 'C': 3, 'D': 4 }
list_of_keys_to_keep = ['B', 'C', 'F']

def remove_fields(d, list_of_keys_to_keep):
    return {key: value for key, value in d.items() if key in list_of_keys_to_keep}

print(remove_fields(d, list_of_keys_to_keep)) # -> {'B': 2, 'C': 3}

Edit: Updated name of list_of_keys_to_remove to list_of_keys_to_keep since this seems to be what it actually represents.

Edit2: Updated after Askers update. The following works for the sample provided:

from collections import MutableMapping

d = {
  'G_1': [
    {
      'ACCOUNTING_RULE_ID': '1',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'RENEW'
    },
    {
      'ACCOUNTING_RULE_ID': '2',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'RENEW'
    },
    {
      'ACCOUNTING_RULE_ID': '3',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'DO_NOT_RENEW'
    },
    {
     'ACCOUNTING_RULE_ID': '4',
      'PAYMENT_TERM_ID': '4',
      'RENEWAL_TYPE': 'RENEW'
    }
  ]
}
list_of_keys_to_keep = ['RENEWAL_TYPE']

def filter_dict(di, keys):
    if not isinstance(di, (dict, list)):
        return di
    if isinstance(di, list):
        return [filter_dict(value, keys) for value in di]
    return {key: filter_dict(value, keys) for key, value in di.items() if key in keys or isinstance(value, (dict, list))}

print(filter_dict(d, list_of_keys_to_keep))

Output:

{'G_1': [{'RENEWAL_TYPE': 'RENEW'}, {'RENEWAL_TYPE': 'RENEW'}, {'RENEWAL_TYPE': 'DO_NOT_RENEW'}, {'RENEWAL_TYPE': 'RENEW'}]}

score 0 · Answer 2 · answered Aug 26 '19 at 11:23

0

try this one:

dict = {"a": 1, "b": 2, "c": 3, "d": 4, "e": 5}
keys_to_preserve = ["e", "b", "c"]

dict_final={k: v for k,v in dict.items() if k in keys_to_preserve}

answered Aug 26 '19 at 11:23

Grzegorz Skibinski

12,624
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This would fail for nested dictionaries. – noobie-php Aug 26 '19 at 11:27
hm, could you share sample input then ? – Grzegorz Skibinski Aug 26 '19 at 11:29
Updated question, please check – noobie-php Aug 26 '19 at 11:34

score 0 · Answer 3 · answered Aug 26 '19 at 12:15

def remove_fields(d, keys_to_preserve):
    if isinstance(d, list):
        return [remove_fields(v, keys_to_preserve) for v in d]
    elif isinstance(d, dict):
        return dict([(k, remove_fields(v, keys_to_preserve)) for k, v in d.items() if k in keys_to_preserve])
    else:
        return d

Remove all keys excepts those mentioned from a dict python3

3 Answers3