How to show a list of children, grouped by category title?

[MarcC]

I have a page with children like this:

Music Samples

  Fugue in D Minor

  La Cucaracha

  Rock You Like A Hurricane

...and each child has a category (using a page select field), in this example Classical, Ethnic, and Rock.

How would I display a list like this?

CLASSICAL

  Fugue in D Minor

ETHNIC

  La Cucaracha

ROCK

  Rock You Like A Hurricane

Thanks!

[Soma]

if you have your categories as pages under a page /categories/ you could loop them and output examples having this category. In this example we assume "category" is the name of the page field in your sample.

<?php
// get all categories
$categories = $pages->get("/categories/")->children;
echo "<ul>";
// loop categories
foreach($categories as $cat) { 
   echo "<li>{$cat->title}";
   // find me all samples having the current category
   $samples = $pages->get("/music-samples/")->find("category=$cat");
   // if any found output them 
   if( count($samples) ) {
       echo "<ul>";
       foreach($samples as $sa) {
           echo "<li>$sa->title</li>";
       }
       echo "</ul>";
   }
   echo "</li>";
}
echo "</ul>";

...accidently submited before finishing code

[MarcC]

Thanks, Soma! I will have a separate categories page/children so that seems like it will work great. Thank you.

[ryan]

Here's another way you could do it too. Though I'd probably use Soma's more straightforward approach unless you are dealing with a large quantity of categories. The reason for that is that this approach (below) is technically a little faster since it's one samples query to cover all categories rather than one samples query per category. But I think Soma's method is easier to follow with more straightforward logic.  

<?php
$cats = $pages->find("parent=/categories/"); 
$samples = $pages->find("parent=/music-samples/, category=$cats, sort=category.name, sort=name"); 
$last = null;
foreach($samples as $s) {
   if($s->category !== $last) {
       if($last) echo "</ul>";
       echo "<h2>{$s->category->title}</h2><ul>";
   }
   echo "<li>{$s->title}</li>";
   $last = $s->category; 
}
echo "</ul>";

[MarcC]

Thanks Ryan, that's pretty slick. I'll give it a try.