我该如何“取消透视"?从 pandas DataFrame的特定列? [英] How can I "unpivot" specific columns from a pandas DataFrame?
本文介绍了我该如何“取消透视"?从 pandas DataFrame的特定列?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个熊猫DataFrame,例如:
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]})
即:
2014 2015 farm fruit
0 10 11 A apple
1 12 13 B apple
2 6 7 A pear
3 8 9 B pear
如何将其转换为:?
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
我尝试过stack
和unstack
,但无法使其正常工作.
I have tried stack
and unstack
but haven't been able to make it work.
谢谢!
推荐答案
这可以通过pd.melt()
完成:
# 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')
结果:
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]
我不确定融解"作为这种操作的名称有多常见,但这就是R的reshape2
程序包中所称的名称,这可能启发了此名称.
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.
这篇关于我该如何“取消透视"?从 pandas DataFrame的特定列?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文