How can I "unpivot" specific columns from a pandas DataFrame?
This can be done with pd.melt():
# value_name is 'value' by default, but setting it here to make it clearpd.melt(x, id_vars=['farm', 'fruit'], var_name='year', value_name='value')Result:
farm fruit year value0 A apple 2014 101 B apple 2014 122 A pear 2014 63 B pear 2014 84 A apple 2015 115 B apple 2015 136 A pear 2015 77 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.