I have a data frame with two columns and would like to fill the second column (which is currently empty) based on the value of the first. If there is "_ab", "_cd" or "_ef" at any position in the first column, "ab", "cd" or "ef" respectively should be in column 2.
That's how it should look:
c1 c2 s_d_ab ab a_cd_aa cd s_sar_ef ef
In Excel I would copy down the formula
=IF(FIND("_ab",A1), "ab", ""), then hide the rows where there was no match and overwrite the formula with
=IF(FIND("_ab",A1), "ab", ""). And so on. Not the most elegant method but it works.
What is the best way to approach this in R?
I managed to get a vector of logical values where the conditions apply (
grepl("_abc", data$c1)) but don't know how to set the value of the second column.