pydata/pandas — pull request #4639 by jreback (2013-08-22 12:28:40+00:00)
Title: PERF: optimize __getitem__ in DataFrame for columns lookup

add as a vbench as well

0.12

```
In [13]: df2 = DataFrame(randn(1000,1),columns=['A'])

In [14]: def h():
....: for i in xrange(10000):
....: df2['A']
....:

In [15]: %timeit h()
10 loops, best of 3: 39.5 ms per loop
```

with PR
```
In [2]: def h():
...: for i in xrange(10000):
...: df2['A']
...:

In [3]: %timeit h()
10 loops, best of 3: 28.7 ms per loop
```