R - Create a new variable where each observation depends on another table and other variables in the data frame

Question

I have the two following tables:

df <- data.frame(eth = c(\"A\",\"B\",\"B\",\"A\",\"C\"),ZIP1 = c(1,1,2,3,5))
Inc <- data.frame(ZIP2 = c(1,2,3,4,5,6,7)         


        

Answer 1

my solution(which maybe seems awkward)

for (i in 1:length(df$eth)) {
    df$Inc[i] <- Inc[as.character(df$eth[i])][df$ZIP[i],]
}