R-创建新列

Question

I have the following data frame:

X1
House-US
House-FR
FR-FR
US-US
FR-US

I would like to create a second column such that:

X1       X2
House-US House 
House-FR House
FR-FR    Ia
US-US    Ia
FR-US    Ir

If a row starts with House then X2 equal to House, If a row has left equal to right (FR-FR) then X2 equal to Ia and Else X2 equal to Ir.

Do you have a solution?

Answer 1

This works:

library(data.table)
setDT(dt)
splitdf <- dt[, X1] %>% strsplit("-") %>% unlist %>% 
  matrix(ncol = 2, byrow = T) %>% data.frame(stringsAsFactors = FALSE)
names(splitdf) <- c("L", "R")
dt$X2 <- ifelse(splitdf[, "L"] == "House", "House", 
                ifelse(splitdf[, "L"] == splitdf[, "R"], "Ia", "Ir"))