在PHP中任意对数组中的对象进行排序

Question

I have a function that is looping over a bunch of items that each look something like this:

[
{"Target":"col-one","Value":0.261},
{"Target":"col-two","Value":0.881},
{"Target":"col-three","Value":0.571},
{"Target":"col-four","Value":0}
]

I would like to re-order each item so that instead of going in ascending order, it goes something like col-one, col-four, col-three, col-two. Is there a relatively simple method that can accomplish this type of arbitrary sorting?

To be clear, I want the result to look like the following:

[
     {"Target":"col-one","Value":0.261}, 
     {"Target":"col-four","Value":0}, 
     {"Target":"col-three","Value":0.571}, 
     {"Target":"col-two","Value":0.881}

]

Answer 1

If you have an array that defines the sort order, like:

$order = ['col-one', 'col-four', 'col-three', 'col-two'];

You can pass it into the usort comparison function and look up the sort index there. I think it's easier if you flip it so the text becomes the key.

$order = array_flip($order);

usort($items, function($a, $b) use ($order) {
    return $order[$a->Target] <=> $order[$b->Target];
});

If you don't flip it first, you have to array_search repeatedly instead. (Unless there's a better way I don't know of.)

usort($items, function($a, $b) use ($order) {
    return array_search($a->Target, $order) <=> array_search($b->Target, $order);
});