If I need to discard a value from an array or from a list of return values, I usually index the list, rather than assign values into undef.

($a, $b)= @array[1,3];

my ($minutes, $hours) = (localtime())[2,3]
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Though the localtime example is artificial, I rarely do anything with list-context localtime(), anymore, other than feed it into Posix::strftime().