laravel 如何在laravel上对对象进行排序？
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How can I sort object on laravel?
提问by Success Man
My object array ($c) like this :
我的对象数组 ($c) 像这样：
Array
(
[0] => stdClass Object
(
[id] => 3
[name] => chelsea.png
)
[1] => stdClass Object
(
[id] => 4
[name] => arsenal.png
)
[2] => stdClass Object
(
[id] => 5
[name] => mu.png
)
[3] => stdClass Object
(
[id] => 1
[name] => city.png
)
)
I want to sort it by id
我想按id排序
If in php normal I try like this :
如果在 php 正常我尝试这样：
function sort_by_id( $a, $b )
{
if( $a->id == $b->id ){ return 0 ; }
return ($a->id < $b->id) ? -1 : 1;
}
usort($c,'sort_by_id');
echo '<pre>';print_r($c);echo '</pre>';
It works
有用
But How can I implement it use laravel?
但是我如何使用laravel来实现它？
I try like this :
我尝试这样：
public function add($param)
{
...
usort($c, $this->sortById());
echo '<pre>';print_r($c);echo '</pre>';die();
...
}
private function sortById($a, $b)
{
if($a->id == $b->id) {
return 0 ;
}
return ($a->id < $b->id) ? -1 : 1;
}
It does not work
这是行不通的
There exist error like this :
存在这样的错误：
Undefined property ... $sortById ...
未定义的属性 ... $sortById ...
How can I solve it?
我该如何解决？
回答by lesssugar
Don't reinvent the wheel. Laravel is a fantastic framework that did lots of work for you already.
不要重新发明轮子。Laravel 是一个很棒的框架，它已经为你做了很多工作。
First, you need to convert your array to a Collection:
首先，您需要将数组转换为集合：
$c = collect($c);
Now, For working with collections, you have a nice set of available methodsyou can work with. In your case, you need the sortBy():
现在，对于使用集合，您有一组很好的可用方法可以使用。在您的情况下，您需要sortBy()：
$sorted = $c->sortBy('id');
Alternatively, you can pass a callback:
或者，您可以传递回调：
$sorted = $c->sortBy(function ($item, $key) {
return $item->id;
});
Both of these will return a Collection object. If you want to get an Array back instead, use all()or toArray()on your result:
这两个都将返回一个 Collection 对象。如果您想取回数组，请在结果上使用all()或toArray()：
$c = $c->all();
// or
$c = $c->toArray();
回答by Nazmul Hasan
Try this
尝试这个
public function add($param)
{
...
usort($c, function($a, $b){
if($a->id == $b->id) {
return 0 ;
}
return ($a->id < $b->id) ? -1 : 1;
});
echo '<pre>';print_r($c);echo '</pre>';die();
...
}
You don't need to use different sortByIdmethod
你不需要使用不同的sortById方法
回答by hassan
If you want a pure php way:
如果你想要一个纯 php 的方式：
In your first case you are trying to pass a procedural functionas a callback to your usortfunction.
在您的第一种情况下，您试图将过程函数作为回调传递给您的usort函数。
When you want to pass a methodfrom a class as a callback you need to pass it as follows:
当您想将类中的方法作为回调传递时，您需要按如下方式传递它：
usort($c, [$this, 'sortById']);
Checkout the third example from the usortman page.
查看usort手册页中的第三个示例。
Note that, you will using the $thisvariable as long as you are within the class. If you want to use the context of another class for example, you will need to pass the instance as follows:
请注意，$this只要您在班级内，就会使用该变量。例如，如果要使用另一个类的上下文，则需要按如下方式传递实例：
$object = new someClass;
usort($c, [$object, 'sortById']);
Also in case if you need to pass a static method you can simply pass it as follows:
另外，如果您需要传递静态方法，您可以简单地按如下方式传递它：
usort($c, ['someClass', 'sortById']);
