I have a pandas DataFrame, eg:
x = DataFrame.from_dict({'farm' : ['A','B','A','B'],
'fruit':['apple','apple','pear','pear'],
'2014':[10,12,6,8],
'2015':[11,13,7,9]})
ie:
2014 2015 farm fruit
0 10 11 A apple
1 12 13 B apple
2 6 7 A pear
3 8 9 B pear
How can I convert it to this: ?
farm fruit value year
0 A apple 10 2014
1 B apple 12 2014
2 A pear 6 2014
3 B pear 8 2014
4 A apple 11 2015
5 B apple 13 2015
6 A pear 7 2015
7 B pear 9 2015
I have tried stack
and unstack
but haven't been able to make it work.
Thanks!
This can be done with pd.melt()
:
# value_name is 'value' by default, but setting it here to make it clear
pd.melt(x, id_vars=['farm', 'fruit'], var_name='year', value_name='value')
Result:
farm fruit year value
0 A apple 2014 10
1 B apple 2014 12
2 A pear 2014 6
3 B pear 2014 8
4 A apple 2015 11
5 B apple 2015 13
6 A pear 2015 7
7 B pear 2015 9
[8 rows x 4 columns]
I'm not sure how common "melt" is as the name for this kind of operation, but that's what it's called in R's reshape2
package, which probably inspired the name here.