pydata/pandas — pull request #8384 by mcjcode (2014-09-25 00:31:10+00:00)
Title: non-existent columns in DataFrame.dropna subset argument now raises KeyError

Bug fix for #8303. Now instead of interpreting a bad column name as the 'last column' of the `DataFrame`, `dropna` will raise a `KeyError` instead. unit test and release note now included.