plpgsql : looping over multidimensional array : getting NULL for subdimension

Hi all,

I'm trying to loop over a multidimensional array and find if any of
the elements in a sub-dimensional array are matching some known criteria but
facing issue with NULL for the sub arrays.

I have a data structure that looks like:

*some_array VARCHAR[][] :=
'{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}'*;

I'm trying to assign the individual sub arrays to other array elements like:

other-array VARCHAR[];

other_array=some_array[1];

and I'm expecting to get '{samba,sarath,sreenivas}' for index 1 and
*{samba,mukhesh,pavan}
*for index 2;*
*however, I'm getting NULL.

Can some one explain the way I can assign subarrays to other array elements
plpgsql?

Thanks and Regards,
Samba