This is the type of thing where a subroutine can be a very useful abstraction: 

frobnitz( $HoA{Foo} )   if  $HoA{Foo};
for my $key (  keys %HoA  ) {
    frobnitz( $HoA{$key} )   if  $key ne "Foo";
}

[download]

If you can't factor it out nicely as a subroutine, you can consider factoring it out as an anonymous code ref so that you can use your lexical variables in it.

Another possibility: 

my %HoA= (
    D=>[4], E=>[5], F=>[6], Foo=>[3], G=>[7], H=>[8],
);
{
    local( $HoA{Foo} )= $HoA{Foo};
    for my $av (  delete $HoA{Foo}, values %HoA  ) {
        print $av->[0], $/   if  $av;
    }
}
print $HoA{Foo}[0], $/;

[download]

But I'd not use that in real® code (and it likely depends on things that at least should be "undefined").

(update) Or use sub to abstract this out differently: 

sub FirstIfKeys {
    my $hv= pop @_;
    my %k;
    @k{ keys %$hv }= (1) x @k;
    my @k;
    for my $key (  @_  ) {
        push @k, $key   if  delete $k{$key};
    }
    return @k, keys %k;
}

    for my $key (  FirstIfKeys( "Foo", \%HoA )  ) {
        ...
    }

[download]

- tye        

In reply to Re: Pulling an item to the front of the list (sub) by tye
in thread Pulling an item to the front of the list by Tanktalus

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