python dict: get vs setdefault

Question

The following two expressions seem equivalent to me. Which one is preferable?

data = [(\'a\', 1), (\'b\', 1), (\'b\', 2)]

d1 = {}
d2 = {}

for key, val in d         


        

Answer 1

You might want to look at defaultdict in the collections module. The following is equivalent to your examples.

from collections import defaultdict

data = [('a', 1), ('b', 1), ('b', 2)]

d = defaultdict(list)

for k, v in data:
    d[k].append(v)

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