Trying to use dplyr to group_by and apply scale()

Question

Trying to use dplyr to group_by the stud_ID variable in the following data frame, as in this SO question:

> str(df)         


        

Answer 1

This was a known problem in dplyr, a fix has been merged to the development version, which you can install via

# install.packages("devtools")
devtools::install_github("hadley/dplyr")

In the stable version, the following should work, too:

scale_this <- function(x) as.vector(scale(x))