[push @ARRAY, LIST] Has the same effect as
   for $value (LIST) {
      $ARRAY[++$#ARRAY] = $value;
   }
but is more efficient.
[download]

The most expensive thing with push might be the (re-)allocation of new memory, so if you would initialize the array with the final size at the start, e.g. $#array = 1000;, and use splice instead of push then you might save time. Please post a compare benchmark here if you code that.

I was curious so I wrote a benchmark for this. (Please note that benchmarks must be interpreted correctly and are sometimes not very meaningful, see 588703.)
Read more... (1026 Bytes)
The results are very interesting:

             Rate     for  splice splice2    push
for      484262/s      --    -59%    -67%    -76%
splice  1169591/s    142%      --    -21%    -42%
splice2 1481481/s    206%     27%      --    -27%
push    2020202/s    317%     73%     36%      --
[download]

As awaited the for loop is the slowest way to do it. push is the fastest of all. Using splice is quite in between of both. The interesting and surprising thing is that splice is faster without pre-allocating the array ('splice2') then with ('splice').

The moral of this seems to be:
Perl build-ins are already very optimized - don't try to replace them with your own Perl code.
If you need something done which is covered by a build-in function - use it. And don't think about it. If you need more performance you are using the wrong programming language!

Seriously, first explain what you mean by the push operation is costly in perl because I don't think everyone agrees with you. Second, what application/domain of yours is it that has such requirements which makes push a particularly costly operation?

Second, what application/domain of yours is it that has such requirements which makes push a particularly costly operation?

What if the array is tied to an ancient mainframe writing to paper tapes on the wrong side of a satellite connection?

As we know that the push operation is costly

We do?

AFAIK, push is O(1), unless I got all the efficiency stuff wrong, which is extremely efficient.

You *could* implement your own Linked-List Data Structure in Perl and add your own push function, but that would be somewhat overkill, and wouldn't be as efficient as push which is implemented in C.