Creating a function that filters a nest dictionary by asking certain values

Question

I am a beginner in python trying to create a function that filters through my nested dictionary through by asking multiple values in a dictionary like

filtered_options = {'a': 5, 'b': "Cloth'}

For my dictionary

my_dict = {1.0:{'a': 1, 'b': "Food', 'c': 500, 'd': 'Yams'},
           2.0:{'a': 5, 'v': "Cloth', 'c': 210, 'd': 'Linen'}}

If I input my dictionary in the filter function with such options I should get something that looks like

filtered_dict(my_dict, filtered_options = {'a': 5, 'b': "Cloth'}) 

which outputs the 2nd key and other keys with the same filtered options in my dictionary.

Answer 1

This should do what you want.

def dict_matches(d, filters):
    return all(k in d and d[k] == v for k, v in filters.items())

def filter_dict(d, filters=None):
    filters = filters or {}
    return {k: v for k, v in d.items() if dict_matches(v, filters)}

Here's what happens when you test it:

>>> filters = {'a': 5, 'b': 'Cloth'}
>>> my_dict = {
...     1.0: {'a': 1, 'b': 'Food', 'c': 500, 'd': 'Yams'},
...     2.0: {'a': 5, 'b': 'Cloth', 'c': 210, 'd': 'Linen'}
... }
>>> filter_dict(my_dict, filters)
{2.0: {'b': 'Cloth', 'a': 5, 'd': 'Linen', 'c': 210}}

Answer 2

You can do this :

import operator
from functools import reduce

def multi_level_indexing(nested_dict, key_list):
    """Multi level index a nested dictionary, nested_dict through a list of keys in dictionaries, key_list
    """
    return reduce(operator.getitem, key_list, nested_dict)

def filtered_dict(my_dict, filtered_options):
    return {k : v for k, v in my_dict.items() if all(multi_level_indexing(my_dict, [k,f_k]) == f_v for f_k, f_v in filtered_options.items())}

So that:

my_dict = {1.0:{'a': 1, 'b': 'Food', 'c': 500, 'd': 'Yams'},
           2.0:{'a': 5, 'b': 'Cloth', 'c': 210, 'd': 'Linen'}}

will give you:

print(filtered_dict(my_dict, {'a': 5, 'b': 'Cloth'}))  
# prints {2.0: {'a': 5, 'b': 'Cloth', 'c': 210, 'd': 'Linen'}}