How can I concatenate dicts (values to values of the same key and new key)? [duplicate]

Question

I have a problem with concatenating dictionaries. Have so much code so I show in example what my problem is.

d1 = {'the':3, 'fine':4, 'word':2}
+
d2 = {'the':2, 'fine':4, 'word':1, 'knight':1, 'orange':1}
+
d3 = {'the':5, 'fine':8, 'word':3, 'sequel':1, 'jimbo':1}
=
finald = {'the':10, 'fine':16, 'word':6, 'knight':1, 'orange':1, 'sequel':1, 'jimbo':1}

It is prepering wordcounts for wordcloud. I dont know how to concatenate values of the keys it is puzzle for me. Please help. Best regards

Answer 1

I would use a Counter from collections for this.

from collections import Counter

d1 = {'the':3, 'fine':4, 'word':2}
d2 = {'the':2, 'fine':4, 'word':1, 'knight':1, 'orange':1}
d3 = {'the':5, 'fine':8, 'word':3, 'sequel':1, 'jimbo':1}

c = Counter()
for d in (d1, d2, d3):
    c.update(d)
print(c)

Outputs:

Counter({'fine': 16, 'the': 10, 'word': 6, 'orange': 1, 'jimbo': 1, 'sequel': 1, 'knight': 1})

Answer 2

import itertools

d1 = {'the':3, 'fine':4, 'word':2}
d2 = {'the':2, 'fine':4, 'word':1, 'knight':1, 'orange':1}
d3 = {'the':5, 'fine':8, 'word':3, 'sequel':1, 'jimbo':1}
dicts = [d1, d2, d3]

In [31]: answer = {k:sum(d[k] if k in d else 0 for d in dicts) for k in itertools.chain.from_iterable(dicts)}

In [32]: answer
Out[32]: 
{'sequel': 1,
 'the': 10,
 'fine': 16,
 'jimbo': 1,
 'word': 6,
 'orange': 1,
 'knight': 1}

Answer 3

def sumDicts(*dicts):
    summed = {}
    for subdict in dicts:
        for (key, value) in subdict.items():
            summed[key] = summed.get(key, 0) + value
    return summed

Shell example:

>>> d1 = {'the':3, 'fine':4, 'word':2}
>>> d2 = {'the':2, 'fine':4, 'word':1, 'knight':1, 'orange':1}
>>> d3 = {'the':5, 'fine':8, 'word':3, 'sequel':1, 'jimbo':1}
>>> sumDicts(d1, d2, d3)
{'orange': 1, 'the': 10, 'fine': 16, 'jimbo': 1, 'word': 6, 'knight': 1, 'sequel': 1}