Re: improve performance

Whenever you want a fast lookup, try to use a hash. This will only work if your elements exist as single lines instead of actual substring matches. Also note that if $strfile contains regex meta characters (like *, . or +, or []) your code will not work as you might think.

Using a hash would result in:

my %lookup = map { $_ => 1 } @arraytocompare;

foreach my $strfile (@tempfiles) {
    if( $lookup{ $strfile } ) {
        push (@newarray, $strfile); 
    };
};
[download]

But I really, really doubt that searching through 8000 array entries will slow your program down that much. Are you certain that this is where your performance bottleneck is?

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Re^2: improve performance by swissknife (Sexton) on Jun 08, 2015 at 10:03 UTC
Thanks Corion. I added few prints and used executed the script using -d option. which clearly shows that this is where the performance bottelneck is. you said if $strfile contains regex meta charachters my code will not will not work as i might have thought... file name has "." before the extension of file. is this statement is valid even if i use hash?	[reply]
Re^3: improve performance by marto (Cardinal) on Jun 08, 2015 at 10:25 UTC
You may want to take a look at Devel::NYTProf for profiling your code.	[reply]
Re^2: improve performance by swissknife (Sexton) on Jun 08, 2015 at 10:41 UTC
I updated the codes with your suggestion which is really faster but does not give the same result as the grep. i find @newarray empty where as it is not. did you consider the NOT operator ! in my original code?	[reply]
Re^3: improve performance by Corion (Patriarch) on Jun 08, 2015 at 10:43 UTC
No, I did not consider it, but you can consider it in your code.	[reply]
Re^4: improve performance by swissknife (Sexton) on Jun 08, 2015 at 12:18 UTC
event after making the change @newarray is empty. `if ( $lookup { !$strfile } ) {`	[reply] [d/l]
Re^5: improve performance by Corion (Patriarch) on Jun 08, 2015 at 12:21 UTC
Re^5: improve performance by Anonymous Monk on Jun 08, 2015 at 12:41 UTC