CODEWITHSUNDEEP
python
vojtam
vojtam

Reputation: 1255

How to make all combinations from a dictionary in python

I have a following dictionary:

origin = {0: [1,2], 1: [1,2,3]}

I would like to get a dictionary that makes combination key_element in value. Desired output is:

{'combo_0_1': 0, 'combo_0_2': 0, 'combo_1_1': 0, 'combo_1_2': 0, 'combo_1_3': 0}

I tried this:

output = {f"combo_{x}_{y}" : 0 for x in origin.keys() for y in origin.values()}

but it returns {'combo_0_[1, 2]': 0, 'combo_0_[1, 2, 3]': 0, 'combo_1_[1, 2]': 0, 'combo_1_[1, 2, 3]': 0} which is not what I want. How can I do it, please?

Upvotes: 2

Views: 60

Answers (4)

Steinn Hauser Magnússon
Steinn Hauser Magnússon

Reputation: 1365

Here's my solution. It generates all the permutations of your lists, and is generalized to accept longer dictionaries.

import itertools

origin = {0: [1,2], 1: [1,2,3]}
perms = list(itertools.product(*origin.values()))
output = {f"combo_"+ "_".join(map(str,p)): 0 for p in perms}
print(output)

Note: You need to map the tuples which itertools.product generates to strings to join them together to your "combo_" keys. Hope this helps!

Upvotes: 0

pho
pho

Reputation: 25490

It helps to write it out as a full loop first. We can convert it to a dict comprehension after that.

You want the second part of the key to be each element of each value of origin. You can get the keys and values of origin in one outer loop, and then in the inner loop, you can loop over the elements in that value.

origin = {0: [1,2], 1: [1,2,3]}
output = {}
for key, val in origin.items():
    for elem in val:
        output[f"combo_{key}_{elem}"] = 0

Or, as a dict comprehension:

output = {f"combo_{key}_{elem}": 0 for key, val in origin.items() for elem in val}

This gives:

{'combo_0_1': 0,
 'combo_0_2': 0,
 'combo_1_1': 0,
 'combo_1_2': 0,
 'combo_1_3': 0}

Upvotes: 2

Ryan Zhang
Ryan Zhang

Reputation: 1935

origin.values() returns all the values, which are lists. This is not what you want.

You want the elements of the current list.

output = {f"combo_{x}_{y}" : 0 for x in origin.keys() for y in origin[x]}

Upvotes: 2

Dani Mesejo
Dani Mesejo

Reputation: 61930

One approach using a dictionary comprehension over dict.items:

origin = {0: [1, 2], 1: [1, 2, 3]}

res = {f"combo_{k}_{v}": 0 for k, vs in origin.items() for v in vs}
print(res)

Output

{'combo_0_1': 0, 'combo_0_2': 0, 'combo_1_1': 0, 'combo_1_2': 0, 'combo_1_3': 0}

Upvotes: 1

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