Custom sorting on a laravel relationship collection

问题

I'm a little stuck on something that usually is quite straight forward. I need to sort records from a hasMany relationship into a custom order based on a certain value and an 'sort order' array.

My code below doesn't work because I'm passing uSort() a eloquent collection and I'm not sure how to get around it.

$go = $this->hasMany('Product')->orderBy('colour','DESC');

$order = array('RED', 'GREEN', 'BLUE', 'YELLOW');

usort($go, function ($a, $b) use ($order) {
    $pos_a = array_search($a->colour, $order);
    $pos_b = array_search($b->colour, $order);
    return $pos_a - $pos_b;
});

return $go;

Maybe I'm missing some amazing laravel magic helper, but I'm stuck. Any thoughts or advice would be much appreciated!

Cheers

回答1:

The usort equivalent for Collection is the sort() method. It takes a callback as a parameter and returns the sorted collection.

So in your case, the solution is:

$go = $go->sort(function ($a, $b) use ($order) {
  $pos_a = array_search($a->colour, $order);
  $pos_b = array_search($b->colour, $order);
  return $pos_a - $pos_b;
});

回答2:

Your sorting will be applied only after you get the result while here $go = $this->hasMany('Product')->orderBy('colour','DESC'); you are just getting an instance of a class which will return can return your result if you apply a get method on it.

For your purpose you have to use sortBy method of laravel collections after you get the result of your data you can find more (laravel Collection sortBy() method) & here is a similar question answer for you https://stackoverflow.com/a/28202985

来源：https://stackoverflow.com/questions/31983216/custom-sorting-on-a-laravel-relationship-collection