How to rename all columns to middle separator in R?

May 2, 2022

I’m looking for an easy solution to rename my columns to only the middle separator. Here’s some mock data.

dat <- data.frame(
  
  subject = paste("Subject", 1:10),
  CT_tib_all = round(rnorm(10, 0.25, 0.03), 2),
  CT_lum_all = round(rnorm(10, 0.25, 0.03), 2),
  CT_tho_all = round(rnorm(10, 0.25, 0.03), 2)
  
)

I’d like to go from this:

    subject CT_tib_all CT_lum_all CT_tho_all
1 Subject 1       0.25       0.27       0.26
2 Subject 2       0.24       0.19       0.21

To this:

    subject        tib        lum        tho
1 Subject 1       0.25       0.27       0.26
2 Subject 2       0.24       0.19       0.21

Thanks!

>Solution :

There may be more elegant solutions, but try this:

colnames(dat)[-1] <- sapply(strsplit(colnames(dat[-1]), "_"), function(x) x[2])

#> dat
#      subject  tib  lum  tho
#1   Subject 1 0.17 0.21 0.20
#2   Subject 2 0.27 0.23 0.28
# ...

This ignores the first (subject) column and sapply() will find everything in between the underscores for the remaining columns.