combining strings

Dear R People:

Suppose I have the following two character vectors:

 xf
 [1] "W" NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA  NA

xg

[1] NA  "k" "h" NA  "g" "r" "j" NA  "v" "d" NA  "v" NA  "z" "r" "r" "i"

I want to end up with

"W" "k" "h" ...

What is the best way to achieve this, please?  I was thinking that if
there is an exclusive "or" that it might work.  I've tried all kinds
of ifs, and ifelse, to no avail.


Thanks,
Erin

Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: erinm.hodgess at gmail.com