You can add all columns in []for aggregation:
print (df.groupby(by=['class_energy'])['ACT_TIME_AERATEUR_1_F1', 'ACT_TIME_AERATEUR_1_F3','ACT_TIME_AERATEUR_1_F5'].sum())
ACT_TIME_AERATEUR_1_F1 ACT_TIME_AERATEUR_1_F3 \
class_energy
high 45.670000 0.000000
low 63.333333 63.333333
medium 0.000000 20.000000
ACT_TIME_AERATEUR_1_F5
class_energy
high 55.940000
low 87.323333
medium 23.990000
You can also use the parameter as_index=False:
print (df.groupby(by=['class_energy'], as_index=False)['ACT_TIME_AERATEUR_1_F1', 'ACT_TIME_AERATEUR_1_F3','ACT_TIME_AERATEUR_1_F5'].sum())
class_energy ACT_TIME_AERATEUR_1_F1 ACT_TIME_AERATEUR_1_F3 \
0 high 45.670000 0.000000
1 low 63.333333 63.333333
2 medium 0.000000 20.000000
ACT_TIME_AERATEUR_1_F5
0 55.940000
1 87.323333
2 23.990000
3:
print (df.groupby(by=['class_energy'], as_index=False)[df.columns[:3]].sum())
class_energy ACT_TIME_AERATEUR_1_F1 ACT_TIME_AERATEUR_1_F3 \
0 high 45.670000 0.000000
1 low 63.333333 63.333333
2 medium 0.000000 20.000000
ACT_TIME_AERATEUR_1_F5
0 55.940000
1 87.323333
2 23.990000
... :
print (df.groupby(by=['class_energy'], as_index=False)[df.columns[:-1]].sum())
class_energy ACT_TIME_AERATEUR_1_F1 ACT_TIME_AERATEUR_1_F3 \
0 high 45.670000 0.000000
1 low 63.333333 63.333333
2 medium 0.000000 20.000000
ACT_TIME_AERATEUR_1_F5
0 55.940000
1 87.323333
2 23.990000