Adding on to the end of an array

Hi all,

I'm very new to PostgreSQL, but this doesn't seem to be in the FAQs, and
I can't find anything 'out there'...

I moved to pgsql because of its array support. I need to be able to append
an element on to an existing array _without knowing its current length_.
I thought that I may be able to find out the length of an array and then
construct a subscript for the next (currently non-existent) element by
just adding 1, but... array_dims() doesn't seem to give easily useable
output.

Does anyone have any idea on this?

Thanks in advance,
Matthew

--
Dr. Matthew C. Forman                   mcf@dmu.ac.uk
School of Engineering & Technology
De Montfort University, Leicester, UK.