hadley/dplyr — pull request #834 by lionelgit (2014-12-05 13:24:35+00:00)
Title: Conditional colwise

This adds a .if argument to summarise_each and mutate_each. `.if` refers to a predicate function that is used to operate selectively on the columns of the data frame.

```
diamonds %>%
mutate_each(funs(as.character), .if = is.factor)
```