Many thanks!

The lookup idea is nice and clean. I will use it as I only have 9 different bits.

However, your second option is the one I was (foolish) looking for. In my code, this could be the line:

# return the first less significant bit set.
return $_ for grep { $bit & 1<<$_ } (0..8)';

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In reply to Re^2: Which bit is set? (inverse of (1<<$value) operator) by wirito
in thread Which bit is set? (inverse of (1<<$value) operator) by wirito

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