You really can't rely on "hash order" for anything, including consistency from run to run. That means that you must ensure that the treatment of non-Foo keys is independent of order.

Your list construction with exists, trinary, and grep looks good to me. That would be my first choice.

Another way would be to construct a sort routine which returns -1 if $a eq 'Foo', 1 if $b eq 'Foo', and zero otherwise. That is likely to be less comprehensible than what you have.

for my $key ( sort {
        $a eq 'Foo' and return -1;
        $b eq 'Foo' and return 1;
        return 0;
    } keys %hash ) {
    # do stuff
}

[download]

That will work fine for hash keys, but may go strange on you if there can be more than one "Foo" in the list.

After Compline,
Zaxo

In reply to Re: Pulling an item to the front of the list by Zaxo
in thread Pulling an item to the front of the list by Tanktalus

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