How can i create a new column in R that will return specific values according to the initial values in R using dplyr?

I have a data frame that looks like this :

i want to create a new column variable that will check each element in the column name and will return a word according to a condition :

1. if the word in the column names ends with a letter to give me the word "table",
2. f the word in the column names ends with a number to give me the word "chair"
3. and if the word in the column names ends with a "NLA" or "NLO" to give me the word "clothing"

Ideally i want the new data frame to look like this:

How I can do this in R using dplyr?

library(tidyverse)
names = c("MARY123L","MARYL123.00","MARYNLO","MARYNLA",
          "JOHN330","JOHNNLA","JOHN123A","JOHN123n456.00","GEORGEJ","GEORGEJ","GEORGEJ","GEORGENLA")
DATA = tibble(names);DATA

>Solution :

Essentially the $ (ends with) metacharacter is what you are looking for.

DATA  |>
    mutate(
        var = case_when(
            grepl("NLA$|NLO$", names) ~ "clothing",
            grepl("[0-9]$", names) ~ "chair", 
            grepl("[[:alpha:]]$", names) ~ "table",
            TRUE ~ "Something has gone wrong - this should never appear"
        )
    )

# A tibble: 12 x 2
#    names          var     
#    <chr>          <chr>
#  1 MARY123L       table
#  2 MARYL123.00    chair
#  3 MARYNLO        clothing
#  4 MARYNLA        clothing
#  5 JOHN330        chair
#  6 JOHNNLA        clothing
#  7 JOHN123A       table
#  8 JOHN123n456.00 chair
#  9 GEORGEJ        table
# 10 GEORGEJ        table
# 11 GEORGEJ        table
# 12 GEORGENLA      clothing

Difference between [[:alpha:]]$ and [a-zA-Z]$

I see another answer was posted at the same time which was pretty similar. It may get different results depending on your locale. For example:

accented_sometimes  <- c(
    "This line ends with a letter", 
    "But this line ends with é"
)

grepl("[[:alpha:]]$", accented_sometimes)
# [1] TRUE TRUE
grepl("[a-zA-Z]$", accented_sometimes)
# [1]  TRUE FALSE

There can also be differences between \\d and [0-9] – see here for more. I suspect this depends heavily on which R you are using – I am using 4.1 on Windows which does not have Unicode support but any later version or the same version on Linux/Mac will do.