I needed to shift out the first bit of a bit vector inside a tight loop, so I benchmarked some alternatives. On a short string, the method below was about 8 times faster than looping with vec().

sub shift_vector {
  my($vector, $length) = @_;
  return pack "b".($length - 1), substr unpack("b$length", $vector), 1
+;
}

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In reply to fast shift of bit vector by hv

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