Gather variables based on condition (R)

问题

I'm working through the book "R for Data Science" and would like to "gather" several variables from the dataset based on a condition (similar to select). Specifically, I want to pick just the continuous variables not the categorical ones.

How can I accomplish this without manually specifying the variables? Below does not work...

library(tidyverse)
diamonds %>%
  gather(key, value, is.numeric(key))

回答1:

I'm sure there are better ways to do this but gather() can take column positions as the selection argument so you can use:

diamonds %>%
   head(10) %>%
   gather(key, value, which(sapply(., is.numeric)))

来源：https://stackoverflow.com/questions/52529822/gather-variables-based-on-condition-r