PHP:使用类似Java的Comparable对自定义类进行排序? [英] PHP: Sorting custom classes, using java-like Comparable?
问题描述
例如,如何使用sort()使自己的自定义类可排序?
How can I make my own custom class be sortable using sort() for example?
我一直在网上搜索以找到使类Comparable成为类的任何方法,就像Java中那样,但是运气不佳.我尝试实现__equals()但没有运气.我也尝试了__toString().我的课看起来像这样:
I've been scanning the web to find any method of making a class Comparable like in Java but without much luck. I tried implementing __equals() but without luck. I've also tried with __toString(). My class looks like this:
class Genre {
private $genre;
private $count;
...
}
我想按降序对它们进行计数,该计数是一个整数...($ genre是一个字符串)
I want to sort them by count which is an Integer, in descending order... ($genre is a string)
推荐答案
You can create a custom sort method and use the http://www.php.net/manual/en/function.usort.php function to call it.
示例:
$Collection = array(..); // An array of Genre objects
// Either you must make count a public variable, or create
// an accessor function to access it
function CollectionSort($a, $b)
{
if ($a->count == $b->count)
{
return 0;
}
return ($a->count < $b->count) ? -1 : 1;
}
usort($Collection, "CollectionSort");
如果您想建立一个更通用的收款系统,可以尝试这样的事情
If you'd like to make a more generic collection system you could try something like this
interface Sortable
{
public function GetSortField();
}
class Genre implements Sortable
{
private $genre;
private $count;
public function GetSortField()
{
return $count;
}
}
class Collection
{
private $Collection = array();
public function AddItem($Item)
{
$this->Collection[] = $Item;
}
public function GetItems()
{
return $this->Collection;
}
public function Sort()
{
usort($this->Collection, 'GenericCollectionSort');
}
}
function GenericCollectionSort($a, $b)
{
if ($a->GetSortField() == $b->GetSortField())
{
return 0;
}
return ($a->GetSortField() < $b->GetSortField()) ? -1 : 1;
}
$Collection = new Collection();
$Collection->AddItem(...); // Add as many Genre objects as you want
$Collection->Sort();
$SortedGenreArray = $Collection->GetItems();
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