Append column name to the beginning of values separated by an underscore

user_14404231 0
Viewed 79

How do you append the column name to the start of each value in the column, separated by a "_", skipping the first column (or, equivalently, choosing the second and third columns)?

multiple=data.frame(id=c(1:6), 
     status=c("good", "bad", "ok", "ok", "good", "bad"), 
     breakfast=c("eggs", "sausage", "eggs", "sausage", "sausage", "eggs"))
# Desired:
#id status breakfast
#1  status_good breakfast_eggs
#2  status_bad  breakfast_sausage
#3  status_ok   breakfast_eggs
#4  status_ok   breakfast_sausage
#5  status_good breakfast_sausage
#6  status_bad  breakfast_eggs
stringr dplyr dataframe r
2 Answers

Here is an option with tidyverse, where we loop across the columns and paste with the corresponding column name (cur_column())

library(dplyr)
library(stringr)
multiple %>%
    mutate(across(c(status, breakfast), ~ str_c(cur_column(), "_", .)))

-output

#  id      status         breakfast
#1  1 status_good    breakfast_eggs
#2  2  status_bad breakfast_sausage
#3  3   status_ok    breakfast_eggs
#4  4   status_ok breakfast_sausage
#5  5 status_good breakfast_sausage
#6  6  status_bad    breakfast_eggs
user_37322710

In base R, we can use Map :

multiple[-1] <- Map(function(x, y) paste(x, y, sep = '_'), 
                     names(multiple)[-1], multiple[-1])

Or with purrr's imap_dfc :

multiple[-1] <- purrr::imap_dfc(multiple[-1], ~paste(.y, .x, sep = '_'))
multiple

#  id      status         breakfast
#1  1 status_good    breakfast_eggs
#2  2  status_bad breakfast_sausage
#3  3   status_ok    breakfast_eggs
#4  4   status_ok breakfast_sausage
#5  5 status_good breakfast_sausage
#6  6  status_bad    breakfast_eggs
user_39629140
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