pandas DataFrame仅对一列进行转置/融化/透视

Question

I have data like this in a pandas DataFrame:

And I would like to transform it to this (in a pandas DataFrame):

I tried to use df.melt(), df.pivot(), and df.T() but it didn't work out for me since they transformed all the columns... Anyone knows how to fix this (using something else than pd Dataframe is also fine, I have my data in a csv file)?

Answer 1

I think you can use pivot with fillna :

print (df)
  name group  weight
0    a     e      60
1    t     g      70
2    p     d      80
3    f     d      40
4    e     e      50
5    l     g      30
6    a     d      20

print (df.pivot(index='name', columns='group', values='weight').fillna(''))
group   d   e   g
name             
a      20  60    
e          50    
f      40        
l              30
p      80        
t              70

Answer 2

您可以使用以下一行代码来做到这一点：

df.set_index(['name','group']).unstack()