From the NannyMUD documentation

LAST CHANGE

2000-12-14

FUNCTION

NAME
        unique_array - Sort an array into arrays of unique groups.


SYNTAX
	mixed *unique_array(int|mixed *array, string uniqfunc, void|mixed del)

DESCRIPTION
	Gives an array of arrays of nonunique objects. The function 'uniqfunc'
	is called on each of the objects in the array. The return values are
	used to group the objects into a number of arrays. For each object
	in such a subarray 'uniqfunc' returned the same value.

 	Then an array on the below form are returned:
   
	   ({
	   ({Same1:1, Same1:2, Same1:3, .... Same1:N }),
	   ({Same2:1, Same2:2, Same2:3, .... Same2:N }),
	   ({Same3:1, Same3:2, Same3:3, .... Same3:N }),
	   ....
	   ....
	   ({SameM:1, SameM:2, SameM:3, .... SameM:N }),
	   })
   


NOTE
	All elements of the array that are not objectpointers are ignored.

	This isn't the most reliable efun. It bugs at times.