Swift may have borrowed it from E, where the half-open variant is `1..!5`, read "from 1 up to, but not including, 5". It is extremely useful for 1-to-n sorts of

Swift may have borrowed it from E, where the half-open variant is `1..!5`, read "from 1 up to, but not including, 5". It is extremely useful for 1-to-n sorts of counting tasks.