wesm/pandas — Issue #612: Pure python multi-key groupby can't handle non-numeric results
Author: wesm
Created: 2012-01-12 00:23:58+00:00
State: open
Labels: Bug

reported by @yarikoptic, could occur fairly easily in 0.6.1, now very pathological to reproduce

```
data = DataFrame({'A' : ['foo', 'foo', 'foo', 'foo',
'bar', 'bar', 'bar', 'bar',
'foo', 'foo', 'foo'],
'B' : ['one', 'one', 'one', 'two',
'one', 'one', 'one', 'two',
'two', 'two', 'one'],
'C' : ['dull', 'dull', 'shiny', 'dull',
'dull', 'shiny', 'shiny', 'dull',
'shiny', 'shiny', 'shiny'],
'D' : np.random.randn(11),
'E' : np.random.randn(11),
'F' : np.random.randn(11)})

def bad(x):
assert(len(x.base) == len(x))
return 'foo'
```