Mutating based on information from two columns in R

I have a dataframe that looks like this:

example <- data.frame(
  sub = c(101, 101, 101, 102, 102, 102),
  trialtype = c("ReframeNeg", "ImmerseNeu", "ImmerseNeg", "ImmerseNeu", "ImmerseNeg", "ReframeNeg"),
  condition = c("Self", "Self", "Self", "Other", "Other", "Other")
)

How can I create a new dataframe that combines the information from the trialtype and condition columns? For example, the first observation will be ‘SelfReframeNeg’ after combining trialtype and condition, which I will simplify to ‘selfrefneg’. The transformation mapping is as follows:

1. SelfReframeNeg = selfrefneg
2. SelfImmerseNeg = selfimmneg
3. SelfImmerseNeu = selfimmneut
4. OtherReframeNeg = socrefneg
5. OtherImmerseNeg = socimmneg
6. OtherImmerseNeu = socimmneut

This is the desired output:

example_solution <- data.frame(
  sub = c(101, 101, 101, 102, 102, 102),
  trialtype = c("ReframeNeg", "ImmerseNeu", "ImmerseNeg", "ImmerseNeu", "ImmerseNeg", "ReframeNeg"),
  condition = c("Self", "Self", "Self", "Other", "Other", "Other"),
  trial = c("selfrefneg", "selfimmneut", "selfimmneg", "socimmneut", "socimmneg", "socrefneg")
)

Thank you!

>Solution :

If you have a limited number of possibile combinations you could use case_when

example %>%
  mutate(trial = paste0(condition, trialtype),
         trial = case_when(
           trial == "SelfReframeNeg" ~ "selfrefneg",
           trial == "SelfImmerseNeg" ~ "selfimmneg",
           trial == "SelfImmerseNeu" ~ "selfimmneut",
           trial == "OtherReframeNeg" ~ "socrefneg",
           trial == "OtherImmerseNeg" ~ "socimmneg",
           trial == "OtherImmerseNeu" ~ "socimmneut",
           TRUE ~ NA
         ))
#>   sub  trialtype condition       trial
#> 1 101 ReframeNeg      Self  selfrefneg
#> 2 101 ImmerseNeu      Self selfimmneut
#> 3 101 ImmerseNeg      Self  selfimmneg
#> 4 102 ImmerseNeu     Other  socimmneut
#> 5 102 ImmerseNeg     Other   socimmneg
#> 6 102 ReframeNeg     Other   socrefneg