[R] dplyr instead of plyr: Help

[Axel Urbiz]

Sorry, this is *related* to a recent post, but not the same. I'd appreciate
your help in getting the same results with the two methods below (the first
using plyr and the second using dplyr. The former works, but not the
latter.)


### Sample data
set.seed(4)df <- data.frame(pred = rnorm(100), y = sample(c(0,1), 100,
replace = TRUE),                 models = gl(2, 50, 100, labels =
c("model1", "model2")))
### using plyr
fooFun <- function(x) {  xcuts <- unique(x$pred)  x$bin <- cut(x$pred,
breaks = xcuts, include.lowest = TRUE)  x <-
dplyr::summarize(dplyr::group_by(x, bin), sumY = sum(y))
x}head(plyr::ddply(df, plyr::.(models), fooFun))

### Using dplyr
fooFun2 <- function(pred, y) {  xcuts <- unique(pred)  bin <- cut(pred,
breaks = xcuts, include.lowest = TRUE)  dft <- data.frame(bin, pred, y)
dft <- dplyr::summarize(dplyr::group_by(dft, bin), sumY = sum(y))  dft}
res_dplyr <- dplyr::mutate(dplyr::group_by(df, models), fooFun2(pred,
y))Error: incompatible size (2), expecting 50 (the group size) or 1
head(res_dplyr)
Thank you.
Axel.

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