python: get the most frequent value in a list of dictionaries

Question

I have a list of dictionaries, having this shape:

xs = [ { \'date\': 1 }, { \'date\': 1 }, { \'date\': 2 }, { \'date\': 1 }, { \'date\': 4 }]

Answer 1

Use a collections.Counter() object to count each date:

from collections import Counter

date_counts = Counter(d['date'] for d in xs)
most_common = {'date': date_counts.most_common(1)[0][0]}

I've assumed you wanted to get the output in the form of a dictionary again here, but you could just use date_counts.most_common(1)[0][0] directly if all you were interested in is that date value.

Demo:

>>> from collections import Counter
>>> xs = [{'date': 1}, {'date': 1}, {'date': 2}, {'date': 1}, {'date': 4}]
>>> date_counts = Counter(d['date'] for d in xs)
>>> {'date': date_counts.most_common(1)[0][0]}
{'date': 1}