How to get values from a "cell" of a "groupby" object?

It's possible by this statement:

>>> df.groupby("A").get_group("foo")["D"]
0    10
2    30
4    50
6    70
7    80
Name: D

Are you thinking of something like this?

>>> df
     A    B  C   D
0  foo  one  1  10
1  bar  one  2  20
2  foo  two  3  30
3  bar  one  4  40
4  foo  two  5  50
5  bar  two  6  60
6  foo  one  7  70
7  foo  two  8  80
>>> df.groupby("A").get_group("foo")["D"]
0    10
2    30
4    50
6    70
7    80
Name: D
>>> df.groupby("A").get_group("foo")["D"].tolist()
[10, 30, 50, 70, 80]