[R] Help with dplyr

[Axel Urbiz]

Hello, 
 
Is there a way to avoid the warning below in dplyr. I’m performing an operation within groups, and the warning says that the factors created from each group do not have the same levels, and so it coerces the factor to character. I’m using this inside a package I’m developing. I’d appreciate your recommendation on how to handle this.
 
library(dplyr)
 
set.seed(4)
df <- data.frame(pred = rnorm(100), models = gl(2, 50, 100, labels = c("model1", "model2")))
 
create_bins <- function (pred, nBins) {
  Breaks <- unique(quantile(pred, probs = seq(0, 1, 1/nBins)))
  bin <- data.frame(pred = pred, bin = cut(pred, breaks = Breaks, include.lowest = TRUE))
  bin
}
 
res_dplyr <- df %>% group_by(models) %>% do(create_bins(.$pred, 10))
Warning message:
  In rbind_all(out[[1]]) : Unequal factor levels: coercing to character
 
Thank you,
Axel.


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