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Re: Re: Optimizing the bejeezus out of a sub

by sgifford (Prior)
on Jun 24, 2003 at 07:38 UTC ( [id://268414]=note: print w/replies, xml ) Need Help??


in reply to Re: Optimizing the bejeezus out of a sub
in thread Optimizing the bejeezus out of a sub

My goal was to speed things up by avoiding copying each value from @_ to $section. While foreach is certainly more aesthetic, some benchmarking shows it to be about the same speed as my loop.

I'm a little surprised by this, actually; I expected using @_ directly to always be faster, since it would avoid copying values.

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Re: Re: Re: Optimizing the bejeezus out of a sub
by IlyaM (Parson) on Jun 24, 2003 at 08:55 UTC
    foreach my $section ( @_ ) { ... } doesn't copy value from @_ to $section. In the loop the variable $section is merely an alias to a currently selected element in @_ array. You can even modify @_ array by assigning a new value to $section. Example: 

    # adds 1 to all elements of array
foreach my $elem (@arr) {
    $elem ++;
}

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    Ilya Martynov, ilya@iponweb.net
    CTO IPonWEB (UK) Ltd
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