You'd almost certainly be faster to unpack the entire string into an array once and then just index into the array: 

my @numbers = unpack '(a4)*', $string;; ## Requires 5.8.x

sub fetchOne {
    my $index = shift;
    return $numbers[ $index ];
}

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In reply to Re: Null-stripping performance by BrowserUk
in thread Null-stripping performance by qiau

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