Is there a dictionary functionality in R

Question

Is there a way to create a \"dictionary\" in R, such that it has pairs? Something to the effect of:

x=dictionary(c(\"Hi\",\"Why\",\"water\") , c(1,5,4))
x[\         


        

Answer 1

See my answer to a very recent question. In essence, you use environments for this type of functionality.

For the higher dimensional case, you may be better off using an array (twodimensional) if you want the easy syntax for retrieving the result (you can name the rows and columns). As an alternative,you can paste together the two keys with a separator that doesn't occur in them, and then use that as a unique identifier.

To be specific, something like this:

tmp<-data.frame(x=c("a", "b"), val=c(5,2))
tmp2<-outer(seq(nrow(tmp)), seq(nrow(tmp)), function(lhs, rhs){tmp$val[lhs] + tmp$val[rhs]})
dimnames(tmp2)<-list(tmp$x, tmp$x)
tmp2
tmp2["a", "b"]