CODEWITHSUNDEEP
pythonlistmultiset
stuffinstuff
stuffinstuff

Reputation: 23

Python: zip 2 lists into a dictonary, del the duplicated keys but keep the values

I'm new to Python. I'm trying to zip 2 lists into a dictionary without losing the values of the duplicated keys and keep values as a list in the dictionary.

Example:

list1 = [0.43, -1.2, 50, -60.5, 50]

list2 = ['tree', 'cat', 'cat', 'tree', 'hat']

I'm trying to get the following outcome:

{'tree': [0.43, -60.5],'cat': [-1.2, 50],'hat': [50]}

Thanks for your help.

Upvotes: 0

Views: 106

Answers (3)

Copperfield
Copperfield

Reputation: 8510

just for completeness, this is how I would have do it in my early days programing 

>>> list1 = [0.43, -1.2, 50, -60.5, 50]
>>> list2 = ['tree', 'cat', 'cat', 'tree', 'hat']
>>> result=dict()
>>> for k,v in zip(list2,list1):
        if k in result:
            result[k].append(v)
        else:
            result[k]=[v]


>>> result
{'hat': [50], 'tree': [0.43, -60.5], 'cat': [-1.2, 50]}
>>>

Upvotes: 0

T. Silver
T. Silver

Reputation: 372

The answer provided by Mike Muller works perfectly well. An alternative, perhaps slightly more pythonic way would be to use defaultdict from the collections library:

from collections import defaultdict

list1 = [0.43, -1.2, 50, -60.5, 50]
list2 = ['tree', 'cat', 'cat', 'tree', 'hat']
d = defaultdict(list)
for k, v in zip(list2, list1):
    d[k].append(v)

Upvotes: 2

Mike Müller
Mike Müller

Reputation: 85442

You can use the setdefault method of the dictionary: 

list1 = [0.43, -1.2, 50, -60.5, 50]
list2 = ['tree', 'cat', 'cat', 'tree', 'hat']
d = {}
for k, v in zip(list2, list1):
    d.setdefault(k, []).append(v)

Results:

>>> d
{'cat': [-1.2, 50], 'hat': [50], 'tree': [0.43, -60.5]}

Upvotes: 2

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