Используйте df.values
с нужными столбцами как:
df = pd.read_csv('dum.txt',sep='\t',header=[0,1],index_col=0)
df[['T1','T2','T3']].values
array([[1.1, 2.1, 3.1],
[1.2, 2.2, 3.2],
[1.3, 2.3, 3.3],
[1.4, 2.4, 3.4],
[1.5, 2.5, 3.5],
[1.6, 2.6, 3.6],
[1.7, 2.7, 3.7],
[1.8, 2.8, 3.8]])
df[['T4','T5']].values
array([[4.1, 5.1],
[4.2, 5.2],
[4.3, 5.3],
[4.4, 5.4],
[4.5, 5.5],
[4.6, 5.6],
[4.7, 5.7],
[4.8, 5.8]])
df[['T6','T7']].values
array([[6.1, 7.1],
[6.2, 7.2],
[6.3, 7.3],
[6.4, 7.4],
[6.5, 7.5],
[6.6, 7.6],
[6.7, 7.7],
[6.8, 7.8]])
Или если у вас есть индексы [0,1,2], [3,4], тогда:
df[df.columns[[0,1,2]]].values
array([[1.1, 2.1, 3.1],
[1.2, 2.2, 3.2],
[1.3, 2.3, 3.3],
[1.4, 2.4, 3.4],
[1.5, 2.5, 3.5],
[1.6, 2.6, 3.6],
[1.7, 2.7, 3.7],
[1.8, 2.8, 3.8]])
ИЛИ:
df.swaplevel(0,1,axis=1).Tag1.values
array([[1.1, 2.1, 3.1],
[1.2, 2.2, 3.2],
[1.3, 2.3, 3.3],
[1.4, 2.4, 3.4],
[1.5, 2.5, 3.5],
[1.6, 2.6, 3.6],
[1.7, 2.7, 3.7],
[1.8, 2.8, 3.8]])