Index isin

import numpy as np
import pandas as pd
df = pd.DataFrame({
    'maths' : [80, 89, 90, 20, 60],
    'science' : [40, 50, 90, 100, 50],
    'language' : [20, 30, 90, 95, 40]
})
df
maths science language
0 80 40 20
1 89 50 30
2 90 90 90
3 20 100 95
4 60 50 40 
df[df.index.isin([1, 2, 4])]
maths science language
1 89 50 30
2 90 90 90
4 60 50 40