Re: Sorting arrays

Don't define separate/related arrays. That's just a bad practice. I realize that in RPG III, we had no alternative.

Hopefully you aren't still using RPG III!

Use an overlay DS for a very simple method. There have been loads of examples posted to this forum in the past. With that technique, you make only one array, and have all of the related fields appear within it and can sort it via SORTA to your heart's content.

Perhaps a better (although more complex) alternative is to load all of your fields into an array of DSes instead of arrays of fields. This is more complex to code because you can't use SORTA, but have to use an API. But data structure arrays provide tons of useful features not available with overlay arrays. (albeit, unrelated to sorting) In an encapsulated, modular, world I would not dream of trying to use overlay arrays, they're too hard to pass in a meaninful way to subprocedures.

When sorting an array of DSes, I would suggest using the qsort() API, which is about the simplest way. There's also the QLGSORT API, but I would steer well away from it, since it's significantly more complex, less versatile, and slower than qsort(). Though it DOES provide better internationalization...

You *could* resort to a work file, but that won't be as fast as an array -- plus, IMHO, it won't be as elegant to code. Whatever you do, stay clear of using a data queue or user index, both of which I've found to be MUCH slower even than a work file, plus they're MORE cumbersome.

Personally, I'd either use an overlay array and SORTA or I'd use a DS array with QSORT. You probably don't need any more options than those two.


Booth Martin wrote:

I'd enjoy following a discussion about sorting related arrays. I have already solved the problem I am about to present, but as I look at my solution it occurs to me that I am embarrassed to show my solution to knowledgeable people. There _has_ to be a better way.

Here's the sceanrio: To display a multi-column load-all subfile and have each column heading clickable. The click would determine which column is sorted. A second click on a clicked column would sort the column in the other direction.

There are images of this at

http://www.martinvt.com/Code_Samples/SFL_Sort/sfl_sort.html

The code is also there. It works. But gads, its awful code.

So, lets define the problem a bit more? A load-all subfile with 5 columns of data How would one define the needed array(s), data structure(s), or whatever(s) so that they can be sorted up or down by a selected column?