Separate a column into 2 columns at the last underscore in R

Question

I have a dataframe like this

id <-c(\"1\",\"2\",\"3\")
col <- c(\"CHB_len_SCM_max\",\"CHB_brf_SCM_min\",\"CHB_PROC_S_SV_mean\")

df <- data.frame(i         


        

Answer 1

We could use extract by capturing as two groups by making sure that the second group have one or more characters that are not a _ until the end ($) of the string

library(tidyverse)
df %>% 
   extract(col, into = c("Measurement", "stat"), "(.*)_([^_]+)$")
#   id   Measurement stat
#1  1   CHB_len_SCM  max
#2  2   CHB_brf_SCM  min
#3  3 CHB_PROC_S_SV mean

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Or using separate with a regex lookaround

df %>% 
   separate(col, into = c("Measurement", "stat"), sep="_(?=[^_]+$)")