array dimension

Hello,

I have a couple of question related to array dimensions.

1. is there a function to get the the highest avaiable index for an array?
I found the function array_dims which returns text (ie: '[1:5]'). Should I scan this returning value to extract what I need?

2. is there a function (or operator) to append new values to the end of an array? (something like || for strings)

3. is there a function (or operator) to merge 2 arrays into one or append the one to the end of the other?

I know this could be done by writing some function, but - maybe - these are already implemented.
Thank you for any suggestion:

Papp Gyozo
- pgerzson(at)freestart(dot)hu