Jason Roth wrote: > I was reading the perldoc for the sort function and I had a few > questions. http://perldoc.perl.org/sort.html says that large arrays > will be shuffled to ensure nlgn runtime. What is the cutoff for > "large arrays" and is there a reason that it isn't simply using a > randomized quicksort?
Download the source and find out for yourself: http://www.cpan.org/src/stable.tar.bz2 :-) > Also http://perldoc.perl.org/functions/sort.html says that sort > returns an alias into the original list and modifying an element of a > list returned by sort actually modifies the element in the original > list. Consider the following code. > > @a = (10,1,9,5,3,4); > @b = sort { $a <=> $b } @a; > $b[0]++; > > If I understand the docs then $b[0]++ should modify @a as well but > this does not seem to be the case. What is going on here? You are not modifying an element of a list, you are modifying an element of an array, and after sort is finished with the list. $ perl -le' @x = ( 40, 20, 50, 30, 10 ); print "@x"; $_++ for sort @x; print "@x"; ' 40 20 50 30 10 41 21 51 31 11 $ perl -le' @x = ( 40, 20, 50, 30, 10 ); print "@x"; map $_++, sort @x; print "@x"; ' 40 20 50 30 10 41 21 51 31 11 John -- Perl isn't a toolbox, but a small machine shop where you can special-order certain sorts of tools at low cost and in short order. -- Larry Wall -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
