python - Filtering grouped DataFrame in Pandas

Question

I am creating a groupby object from a Pandas DataFrame and want to select out all the groups with > 1 size.

Example:

     A  B
0  foo  0
1  bar  1
2  foo  2
3  foo  3

The following doesn't seem to work:

grouped = df.groupby('A')
grouped[grouped.size > 1]

Expected Result:

A
foo 0
    2
    3

Answer 1

As of pandas 0.12 you can do:

>>> grouped.filter(lambda x: len(x) > 1)

     A  B
0  foo  0
2  foo  2
3  foo  3