You may be interested in learning splice, map, and grep as well. Perl is truly rich in methods of manipulating lists and arrays.

Pronouncements like your programming friend made about what can be done with lists usually have a hidden assumption about how the list is implemented at low level. That could be linked nodes, fixed records adjacent in memory, or some flavor of tree. Each has strengths and weaknesses in the fundamental operations of insertion, deletion, searching, and indexing.

After Compline,
Zaxo