Translate a vector based on a matrix on R -

i have indicate matrix, this:

john   1 ann   2 ruby   3 clair   4 

so want translate vector number keep order, this:

(john,ann,john,clair,john,ruby,ann,john,ruby)->(1,2,1,4,1,3,2,1,3) 

i don't know how r(without loop).

please me. thks

even in updated example, can use ?match @pascal describes. don't match letters.

# generate example df <- data.frame(input=c("john", "ann", "ruby", "clair"),                   output=1:4) x <- c("john", "ann", "john", "clair", "john",         "ruby", "ann", "john", "ruby") #  # if output indeed 1:nrow(df) match(x, df[, "input"]) # if output different df[match(x, df[, "input"]), "output"]