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