Condensing a list, keeping track of duplicates

Question

A pretty basic question for you guys:

I've got a list of dates, but there are some duplicates. I'm trying to convert it into a list of two element lists, where element one is the date, and element two is the number of times it appears.

dates is my list of dates, and condensedDates is the new list I'm trying to make.

for i in dates:
    a = [i, 0]
    if dateCount.count(i) == 1:
        a[1] = a[1] + 1
    if dateCount.count(i) == 0:
        dateCount.append(i)

I'm just stuck for what to do next. Obviously a resets on every for loop. Any suggestions? I'm pretty new to this

Please also mention the sample list you have with the question — Moinuddin Quadri, Dec 19 '16 at 17:05

score 2 · Accepted Answer · answered Dec 19 '16 at 17:07

2

You may use collections.Counter as:

>>> from collections import Counter

>>> my_list = ['a', 'b', 'c', 'a', 'd', 'e', 'b', 'a']
>>> Counter(my_list).items()
[('a', 3), ('c', 1), ('b', 2), ('e', 1), ('d', 1)]

answered Dec 19 '16 at 17:07

Moinuddin Quadri

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Condensing a list, keeping track of duplicates

1 Answers1