How to merge and sum duplicates in python?

Question

I have a numpy array:

   [2016-10-20 00:00:00, 6, 17],
   [2016-10-20 00:00:00, 0, 21],
   [2017-09-11 00:00:00, 7, 22],
   [2017-09-11 00:00:00, 5, 30],
   [2017-09-11 00:00:00, 2, 40]

Is there an easy way to merge the the rows with the same dates and sum up the values belonging to the same date?

For the example above, It should look like this:

   [2016-10-20 00:00:00, 6, 38],
   [2017-09-11 00:00:00, 14, 92]

That doesn't look like a valid NumPy array format. Also, are the dates sorted in that sequence? — Divakar
– Divakar, Commented Mar 12, 2016 at 18:16

ChrisP · Accepted Answer · 2016-03-12 18:58:05Z

4

I suggest using pandas for this:

import pandas as pd

d = pd.DataFrame([
    ['2016-10-20 00:00:00', 6, 17],
    ['2016-10-20 00:00:00', 0, 21],
    ['2017-09-11 00:00:00', 7, 22],
    ['2017-09-11 00:00:00', 5, 30],
    ['2017-09-11 00:00:00', 2, 40]
])

d.groupby([0]).aggregate(sum)

#                       1   2
# 0
# 2016-10-20 00:00:00   6  38
# 2017-09-11 00:00:00  14  92

Note that pandas.DataFrame accepts a numpy array as input.

answered Mar 12, 2016 at 18:58

ChrisP

5,9721 gold badge36 silver badges36 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to merge and sum duplicates in python?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related