In [2]:
df
Out[2]:
a b c
1 4.0 7 10.0
2 5.0 8 11.0
3 NaN 9 NaN

Return rows by label.

In [3]:
df.loc[2:2]
Out[3]:
a b c
2 5.0 8 11.0

Return rows by location.

In [4]:
df.iloc[1:2]
Out[4]:
a b c
2 5.0 8 11.0

Return rows using a function.

In [5]:
df.iloc[lambda r: r.index % 2 == 0]
Out[5]:
a b c
2 5.0 8 11.0