python - pandas csv到行和列的数据框转换

Question

这个问题已经有答案了:

How can I pivot a dataframe? (5 个回答)

已关闭 4 年前。

我有这个 CSV 数据

C,kernel,error
0.001,linear,0.03
0.001,poly,0.04
0.01,linear,0.01
0.01,poly,0.03
0.1,linear,0.00
0.1,poly,0.02
1.0,linear,0.00
1.0,poly,0.01
10.0,linear,0.00
10.0,poly,0.01

使用 pandas，如何创建一个包含一列唯一 C 值、与该 C 值关联的内核以及错误的数据帧？

预期输出

C, linear, poly
0.001,0.03,0.04  <-- error values
0.01,0.01,0.03
0.1,0.00,0.02
1.0,0.00,0.01
10,0.00,0.01

Answer 1

您可以使用pd.DataFrame.pivot :

res = df.pivot(index='C', columns='kernel', values='error')

print(res)

kernel  linear  poly
C                   
0.001     0.03  0.04
0.010     0.01  0.03
0.100     0.00  0.02
1.000     0.00  0.01
10.000    0.00  0.01