No, I don't think I get your point. You're doing a lot of looping and returning an array that you create in the loop. You can't return the array during the loop because it's not actually finished yet.

Your original post mentions $|=1 (aka $OUTPUT_AUTOFLUSH if you use English). This is for sending output (as with print) without buffering (see perlvar). If your loop looks like this:

$| = 1;  # output autoflush
for ( 1 .. $x ) {
    push @array, $_;
    print "I did '$x'!  Yay!\n";
}
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...then in that case, $| makes a difference. If you're not actually generating any output during the loop, it won't matter. The $| setting is only for output.

If you leave $| to the default value (buffering), you'll get groups of lines at a time instead of each individually. Again, none of this has anything to do with looping or returning data.

Your array data doesn't exist until the loop completes.

Perhaps you mean you want to remove the explicit loop? If so, you might try using map to generate your series in a single statement. However, you'll still have your memory problems.

Or maybe you're interested in a continuation? That is, a function that you can just get the next value from when you want it? That would let you work with your data without having to store it in an array.

#!/usr/bin/perl -w
use strict;
use warnings;

# Build a continuation to return the series of interest
sub make_a_continuation {
    # Variables the continuation uses
    my $max = shift;
    my $first = 1;

    # Return an anonymous function ref to generate next item
    return sub {
        $first++ * 100 + 300 + 200;
    }
}

# Build a couple continuations
my $get_next = make_a_continuation(50);
my $get_another = make_a_continuation(100);
# None of the data elements in the two series exists yet!  You'll
# have to create them as you need them by calling the appropriate
# continuation, e.g. &$get_next.

for my $loop (1..100) {
    # Randomly create & print items from the series
    print &$get_next . "\n" if rand(5) < 2.0;
    print &$get_another . "\n" if rand(5) < 3.5;
}
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$ ./continuation.pl
Next: 600
Another: 600
Another: 700
Next: 700
Next: 800
Another: 800
Next: 900
Another: 900
Another: 1000
Another: 1100
Next: 1000
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I personally believe that in addition to what that has already been said, there are some issues with your code:

• it is a supposedly minimal snippet but it contains an unnecessary assignment to $r, which is not used afterwards;
• it contains a bare return outside of a sub which is a valid construct, but a suspect one as well, and not likely to do what that you want.

I guess we need to wait untill the loop finish the process and entire data in the memory. Instead of doing this, Is there any ways to return the array data then and there. Did you get my point?

Not at all... do you want to randomly return asynchronously copies of your array while it is being filled? It should be doable with threads, but... why so?!?