> I'd like to search that array and push to it if a value isn't there.
> At the moment I'm dereferencing the array, searching/pushing it and
> the passing it back to the class as an array ref again. So this mean
> copying the array. Code:
>
> my @used_images = @{$_[0]->{_used_images}};
> foreach (@imgids) {push(@used_images, $_) unless (grep { /^$_$/ }
> @used_images);}
> $_[0]->{_used_images} = [EMAIL PROTECTED];
>
The way you wrote it is very confusing, and I actually doubt you get
the result you want (too lazy to run it). Avoid relying on $_ when you
have to use it with different values on the same line (e.g. you push $_
to @used_images AFTER it has been reassigned by the grep on the last
element of @used_images).
To answer your actual question - no you don't have to copy the array.
You can work on an aray behind a reference just like you did the
assignment to @used_images in the first line.
Also using eq instead of a regex (which in your case is equivalent to an
eq anyway) is times faster.
foreach my $new_id (@imgids) {
unless (grep { $_ eq $new_id} ( @{$_[0]->{_used_images}} ) ) {
push @{$_[0]->{_used_images}}, $new_id;
}
}
And last but not least - if you need unique values why don't you just
use a hash for this data branch? If @imgids contains 500 elements and
$_[0]->{_used_images} contains 5000 you will run through the inner loop
exactly 2500000 times which will cost you even on a very fast machine.
Peter
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