Bioequivalence and Bioavailability Forum

Hi all, especially the R experts out there,

I have a vector like
a=c(1,1,2,2,3,5,5,6,6,7,8,8,9,9)
and I would like to rename/reorder/resomething this vector so that
a=c(1,1,2,2,3,4,4,5,5,6,7,7,8,8)

They are actually factor levels.

So far I took a look at reorder, rank, and sort and googled around but I am not really getting anywhere. I have written a clumsy function that does the trick, but I am sure this can be achieved with a one-liner somehow.

Anyone able to tell how?

Thanks a lot in advance and have a great day.