How to pivot a grouped object with pandas

Question

I have the below table:

+-----------+------+-------+
| member_id | year | count |
+-----------+------+-------+
|         1 | 2012 |     1 |
|         1 | 2013 |     0 |
|         1 | 2014 |     1 |
|         2 | 2012 |     2 |
|         2 | 2013 |     0 |
|         2 | 2014 |     1 |
+-----------+------+-------+

and i'd like to turn it into this:

+-----------+------------+------------+------------+
| member_id | count_2012 | count_2013 | count_2014 |
+-----------+------------+------------+------------+
|         1 |          1 |          0 |          1 |
|         2 |          2 |          0 |          1 |
+-----------+------------+------------+------------+

I tried grouping and then pivoting and also just pivoting, but the pivot requires and aggfunc, and I'm not trying to change the values, just reshape it.

`df.pivot('member_id', 'year', 'count')` or `df.set_index(['member_id', 'year']).unstack()` — It_is_Chris, Mar 18 '19 at 16:07

score 1 · Accepted Answer · answered Mar 18 '19 at 16:12

1

df = df.pivot(index='member_id',columns='year', values='count')

If you dont want to have member_id as index:

df = df.pivot(index='member_id',columns='year', values='count').reset_index()

answered Mar 18 '19 at 16:12

Antonio Andrés

149
11

How to pivot a grouped object with pandas

1 Answers1