If order need not be preserved I think a hash slice is quicker.

$ perl -MBenchmark=cmpthese -Mstrict -wE '
> my @arr; 
> push @arr, int rand 20 for 1 .. 1000;
> cmpthese(
>    -5,
>    {
>        grep  => sub
>           {
>               my %seen;
>               my @uniq = grep ! $seen{ $_ } ++, @arr;
>           },
>        slice => sub
>           {
>               my %seen;
>               @seen{ @arr } = ( 1 ) x @arr;
>               my @uniq = keys %seen;
>           },
>    }
>    );'
        Rate  grep slice
grep  3041/s    --  -29%
slice 4260/s   40%    --
$

[download]

However, take my benchmarks with a pinch of salt, I often make a complete dog's breakfast of them :-(

I hope this is of interest.

Cheers,

JohnGG

In reply to Re^2: Can't remove the the duplicate element when it's the last one in the array by johngg
in thread Can't remove the the duplicate element when it's the last one in the array by littlehorse

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