Re: [FWP] Formatting integer sets with ranges

[Rick <rklement@pacbell.net>]

Yitzchak Scott-Thoennes wrote:
> 
> I had to write a throwaway script to (among other things) print a
> sorted array of integers like 1,2,3,5,6,8,10 as a list of ranges like
> 1-3,5-6,8,10.  I remembered that there was a module to do this (it is
> Set::IntSpan) but I didn't want to take the time to search, download,
> install, and figure it out.  So after a couple minutes I came up with
> this:
> 
>         $pre = '';
>         while ($nxt = shift @issues) {
>             print $pre, $nxt;
>             if (($issues[0] || 0) == $nxt+1) {
>                 $nxt = shift @issues while ($issues[0] || 0) == $nxt+1;
>                 print "-$nxt";
>             }
>             $pre = ',';
>         }
>         print "\n";
> 
> I'll never need the script again, but it seems like there should be a
> somewhat simpler way to do this (along the lines of "print map ...").
> Any takers?
>

A long time ago I did it something like this:

# put in arbitrary marker
# change to comma or dash by value test
# then throw out runs of dashes

  $_ = join ':', @issues;
  1 while s/(\d+):(\d+)/$1 . (qw(, -))[$1 + 1 == $2] . $2/e;
  s/-[^,]+-/-/g;
  print "$_\n";


Rick

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