Replace specific values in data frame in R

October 9, 2023

Below you can see my data.

df <- data.frame(
  R1 = c("EFTA : 0 / BAA/GBR : 0 / ES : 2", "10","EFTA : 0 / BAA/GBR : 0 / ES : 2","NA"),
  R2 = c("-", "EFTA : 0 / BAA/GBR : 0 / ES : 2","NA","CEFTA : 0 / MSA/GB : 0 / TR : 0")
)

Now I want to replace value from column R1 into column R2, but only if values in R2 are "-" or "NA". Final output that I expect is shown in table below.

So please can anybody help me to solve this ?

>Solution :

library(dplyr)

df |>
  mutate(R2 = replace(R2, R2 %in% c("-", "NA"), NA),
         R2 = coalesce(R2, R1),
         R1 = ifelse(R1 == R2, "", R1))

By using replace to turn those values into NA, we can then use coalesce to replace NA values when there is a value in R1.

Output

  R1                              R2
1    EFTA : 0 / BAA/GBR : 0 / ES : 2
2 10 EFTA : 0 / BAA/GBR : 0 / ES : 2
3    EFTA : 0 / BAA/GBR : 0 / ES : 2
4 NA CEFTA : 0 / MSA/GB : 0 / TR : 0