Ah, no need to splice. 

# @keys = keys %hash;  # done ONCE
# ($k,$v) = rhe(%hash,@keys);

sub rhe (\%\@) {
    my( $hv, $av )= @_;
    my $idx= rand @$av;
    my $key= $av->[$idx];
    my $val= delete $hv->{$key};
    my $last= pop @$av;
    $av->[$idx]= $last   if  $idx < @$av;
    return( $key, $val );
}

[download]

As for saving space, I don't see you really making use of the hash here so you could do: 

@keys = keys %hash;
@vals = values %hash;
undef %hash;

[download]
If the keys are long, then you could also probably save a bit of space by storing reference to the keys in the array instead of the key values themself (or maybe not).

        - tye (but my friends call me "Tye")

In reply to (tye)Re: Efficient random hash stuff by tye
in thread Efficient random hash stuff by japhy

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