Is there a way to append a column name to the end of each observation within respective columns?

Question

[R] I am trying to modify the format of my data frame (df) so that the column name is appended to each observation within that column within R. For example:

Soccer_Brand	Basketball_Brand
Adidas	Nike
Nike	Under Armour

And want to get it to look like

Soccer_Brand	Basketball_Brand
Adidas_Soccer_Brand	Nike_Basketball_Brand
Nike_Soccer_Brand	Under_Armour_Basketball_Brand

Im attempting a market basket analysis and need to remove column names eventually. However I will lose the information on what sport the brand belongs to without appending the column names to the observations themselves. Essentially I wont be able to tell whether a 'nike' entry belongs to soccer or basketball.

I've used Excel formulas to hack a solution thus far but want my R script to be self contained. I haven't found any solutions out there for this in R.

Answer 1

You can paste a column's name onto its contents. Just iterate through all the columns. Doing so with lapply allows the one-liner:

df[] <- lapply(seq_along(df),\(i) paste(df[[i]], names(df)[i], sep = "_"))

resulting in

df
#>          Soccer_Brand              Basketball_Brand
#> 1 Adidas_Soccer_Brand         Nike_Basketball_Brand
#> 2   Nike_Soccer_Brand Under Armour_Basketball_Brand

---

Data from question in reproducible format

df <- data.frame(Soccer_Brand     = c("Adidas", "Nike"),
                 Basketball_Brand = c("Nike", "Under Armour"))

Answer 2

Or using an option in tidyverse

library(dplyr)
library(stringr)
df <- df %>% 
   mutate(across(everything(), ~ str_c(.x, cur_column(), sep = "_")))

-output

df
         Soccer_Brand              Basketball_Brand
1 Adidas_Soccer_Brand         Nike_Basketball_Brand
2   Nike_Soccer_Brand Under Armour_Basketball_Brand