That's far too complicated a solution for me to leave standing after a code review if I was doing this formally.

If you merely want to avoid processing items based on their value, use a next in a foreach:

for $item (@list) {
  next if $item == 2 or $item == 4;
  ... rest of processing ..
}
[download]

If you want a list that contains all but those items, then use a grep, as you said:

my @newlist = grep { $_ != 2 and $_ != 4 } @list;
[download]

But your for-loop monstrosity is ripe for off-by-one errors, and even if you got everything just right, your maintenance programmer would almost certainly break it.

Extra special hint: walking a list with for-style loops is almost always WRONG. Yes, there are counterexamples, but start with that.

-- Randal L. Schwartz, Perl hacker