This is a better way to use closures

usort($your_data, function($a, $b)
{
    return strcmp($a->name, $b->name);
});

Please note that this is not in the PHP documentation, but if you are using version 5.3, closures are supported and callable parameters can be provided.

Using usort, here is an example adapted from the manual:

function cmp($a, $b) {
    return strcmp($a->name, $b->name);
}

usort($your_data, "cmp");

You can also use any callable as the second parameter. Here are some examples:

• Using Anonymous functions (starting with PHP 5.3)

  usort($your_data, function($a, $b) {return strcmp($a->name, $b->name);});

• Used inside the class

  usort($your_data, array($this, "cmp")); // "cmp"应该是类中的一个方法

• Using arrow functions (starting with PHP 7.4)

  usort($your_data, fn($a, $b) => strcmp($a->name, $b->name));

Also, if you want to compare values, fn($a, $b) => $a->count - $b->countas a "comparison" function should do the trick , or, if you want to do the same thing another way, starting with PHP 7 you can use the spaceship operator, like this: fn($a, $b) =&gt ; $a->count <=> $b->count.