CODEWITHSUNDEEP
pythondictionary
Adel M Elshahed
Adel M Elshahed

Reputation: 11

Setting an existing dictionary's values to all zeros

If I have this dict: 

dict1 = {"Key1": [[1, 3, 4], [2, 5, 8]], "key2": [4, 5]}

How can I set all the values to 0?

Output should be like this:

dict1 = {"Key1": [[0,0,0], [0,0,0]], "key2": [0,0]}

Upvotes: 0

Views: 70

Answers (3)

kederrac
kederrac

Reputation: 17322

you can mutate your dict1 values so that the most inner lists to have only 0 as elements: 

def change_to_zero(nested_list):
    if isinstance(nested_list[0], list):
        for l in nested_list:
            change_to_zero(l)
    else:
         nested_list[::] = [0] * len(nested_list)

change_to_zero(list(dict1.values()))

print(dict1)

output:

{'Key1': [[0, 0, 0], [0, 0, 0]], 'key2': [0, 0]}

this approach assumes that your dict values are lists of different levels of nestedness and the most inner list doesn't have lists as elements, only integers (for your example)

Upvotes: 0

Nick
Nick

Reputation: 147206

You can do this with a recursive function that zeros each element of a list or dictionary that is passed to it:

dict1 = { "Key1" :[ [1, 3, 4], [2 , 5 , 8]], "key2" : [4, 5] }

def zero(e):
    if type(e) is list:
        return [zero(v) for v in e]
    elif type(e) is dict:
        return {k : zero(v) for k, v in e.items()}
    return 0

dict1 = zero(dict1)
print(dict1)

Output:

{'Key1': [[0, 0, 0], [0, 0, 0]], 'key2': [0, 0]}

Note that this generates a new dictionary rather than mutating the original one.

Upvotes: 3

martineau
martineau

Reputation: 123491

You can modify the dictionary "in-place" — i.e. without replacing it with a new one — via a relatively simple recursive function:

def zero_values(obj):
    if isinstance(obj, dict):
        for k, v in obj.items():
            obj[k] = zero_values(v)
        return obj
    elif isinstance(obj, list):
        for i, v in enumerate(obj):
            obj[i] = zero_values(v)
        return obj
    else:
        return 0

dict1 = { "Key1" :[ [1, 3, 4], [2 , 5 , 8] ], "key2" : [4, 5] }
zero_values(dict1)
print(dict1)  # -> {'Key1': [[0, 0, 0], [0, 0, 0]], 'key2': [0, 0]}

Upvotes: 1

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