hadley/plyr — Issue #73: mutable summarize with **ply
Author: baptiste
Created: 2012-01-10 06:37:57+00:00
State: open

Feature request: allow reference to previous transformations with summarize in ddply. Example,

``` r
d = data.frame(a = 1:6, b =gl(2, 3), c = letters[1:6])
ddply(d, .(b), summarize, ind = which.max(a), c = c[ ind ])
```