wesm/pandas — Issue #358: Single column groupby does not set name
Author: wesm
Created: 2011-11-10 21:50:56+00:00
State: open
Labels: Bug

```
In [2]: paste
df = DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
'foo', 'bar', 'foo', 'foo'],
'B' : ['one', 'one', 'two', 'three',
'two', 'two', 'one', 'three'],
'C' : np.random.randn(8),
'D' : np.random.randn(8)})
## -- End pasted text --

In [3]: df
Out[3]:
A B C D
0 foo one -2.096 0.4961
1 bar one -0.8738 -1.074
2 foo two -0.01376 -0.956
3 bar three 0.996 0.368
4 foo two -1.396 -0.3736
5 bar two 0.7779 0.4091
6 foo one -0.1221 1.26
7 foo three -0.9718 -0.4734

In [4]: df.groupby('A').mean()
Out[4]:
C D
bar 0.3001 -0.09914
foo -0.9199 -0.00939

In [5]: df.groupby(['A', 'B']).mean()
Out[5]:
C D
A B
bar one -0.8738 -1.074
three 0.996 0.368
two 0.7779 0.4091
foo one -1.109 0.878
three -0.9718 -0.4734
two -0.7048 -0.6648
```