You don't usually need the (1) x @arr when doing stuff like this. This would suffice perfectly:

@check{@array_to_test} = ();         # Sets them all to undef
$all_the_same = (keys %check <= 1);  # empty @ary = true too? heck, wh
+y not?
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If you were checking a true/false condition based on the presence of any of the keys, the 1 would be needed, but all we're interested in here is the keys.