in reply to Better way of writing "find the missing number(s)"

There hasn't been a regex solution yet, so here's one as a one-liner :)

perl -le '"@{[sort{$a<=>$b}19,17,22,23,24,15,16,25..35]}"=~/\b\d+ (?=( +\d+))(?{push@a,$&+1..$1-1})(*F)/;print"@a"'