Duplicating columns whose names are suffixed with numbers and adding an offset to the new column nam-CodePudding

I would like to duplicate a certain subset of columns whose names are suffixed by numbers. To the nummerical suffixes of new columns should be added a certain offset (in the following example it's 12).

Source data frame:

Desired data frame:

Unfortunately, my code isn't working at all and on top, it seems unreasonably complicated.

library(tidyverse)

df <- data.frame(
  v_1 = c('Aira', 'Ben', 'Cat'),
  v_2 = c(23, 32, 27),
  v_3 = c(90, 98, 95)
)

# Duplicate columns using mutate   across
df2 <- df %>% mutate(
  across(
    .cols = starts_with('v'),
   .names = paste("x", toString(strtoi(strsplit({.col}, '_')[[1]][2])   12, sep="_"))
  )
)

CodePudding user response：

this works for the given example, using dplyr::across():

df %>% 
    dplyr::mutate(across(v_1:v_3, 
                         .fns = ~ .x, 
                         .names = "x_{as.numeric(stringr::str_sub(.col, 3, 3)) 12}"))

   v_1 v_2 v_3 x_13 x_14 x_15
1 Aira  23  90 Aira   23   90
2  Ben  32  98  Ben   32   98
3  Cat  27  95  Cat   27   95

CodePudding user response：

bind_cols(
  df, 
  df %>% rename_with(
    .cols=starts_with("v_"),
    .fn=\(x) paste0("v_",as.numeric(stringr::str_extract_all(x,"\\d")) 12)
  )
)

You can also use mutate(across()) as you were planning, like this:

df %>% mutate(across(
  .cols=starts_with("v_"),
  .names="{paste0('v_',as.numeric(stringr::str_extract(col,'\\\\d')) 12)}"
))