Use rle to group by runs when using dplyr

Question

In R, I want to summarize my data after grouping it based on the runs of a variable x (aka each group of the data corresponds to a subset of the data where cons

Answer 1

If you explicitly create a grouping variable g it more or less works:

> dat %>% transform(g=with(rle(dat$x),{ rep(seq_along(lengths), lengths)}))%>%                                   
 group_by(g) %>% summarize(mean(y))
Source: local data frame [4 x 2]

      g mean(y)
  (int)   (dbl)
1     1     2.0
2     2     4.5
3     3     6.0
4     4     7.0

I used transform here because mutate throws an error.