R: How to split a specific column based on symbol in R? [duplicate]

Answer 1

Like this:

df <- data.frame(drug1 = c("B+A", "B", "A+C"))
df
df$drug2 <- lapply(strsplit(as.character(df$drug1), "\\+"), "[", 2)
df$drug1 <- lapply(strsplit(as.character(df$drug1), "\\+"), "[", 1)
df

resulting

> df
  drug1 drug2
1     B     A
2     B    NA
3     A     C
>