Merge two vectors by element name

Question

I have two vectors:

> str(A)
 Factor w/ 2 levels "neg","pos": 1 NA NA 1 1 2 NA NA 1 2 ...
> str(B)
 Factor w/ 2 levels "neg","pos": 1 1 1 1 2 1 2 1 1 2 ...
 - attr(*, "names")= chr [1:120] "2" "3" "7" "8" ...

and I need to merge them, such that the values from B get placed into A in the position determined by the name of the element in B. I tried

sapply(names(B), function(x) {
  assign ("m", x)
  A[x]  <- B["m"]   })

but the results are all weird:

2.NA   3.NA   7.NA   8.NA  12.NA  14.NA   
<NA>   <NA>   <NA>   <NA>   <NA>   <NA>

I think is some type of assignemnt problem but can't figure it out.

Answer 1

A[as.numeric(names(B))] <- B