akleeman/xray — pull request #62 by shoyer (2014-03-11 22:28:17+00:00)
Title: Modified Dataset.replace to replace a dictionary of variables

The resulting function is more flexible and provides a canonical solution for a common pattern I found myself writing with xray:
- Create a new dataset based on some (but not all) variables from an existing
dataset.
- Add in new variables, often of that same name as the variables I removed
from the original dataset.