带参数的 PHP array_filter [英] PHP array_filter with arguments

问题描述

我有以下代码:

function lower_than_10($i) {
    return ($i < 10);
}

我可以用来过滤这样的数组:

that I can use to filter an array like this:

$arr = array(7, 8, 9, 10, 11, 12, 13);
$new_arr = array_filter($arr, 'lower_than_10');

如何将参数添加到 lower_than_10 以便它也接受要检查的数字?就像，如果我有这个:

How can I add arguments to lower_than_10 so that it also accepts the number to check against? Like, if I have this:

function lower_than($i, $num) {
    return ($i < $num);
}

如何从 array_filter 传递 10 到 $num 或任何数字来调用它?

how to call it from array_filter passing 10 to $num or whatever number?

推荐答案

作为@Charles 使用闭包的解决方案，你实际上可以找到一个例子 在文档页面的评论 中.这个想法是，您创建一个具有所需状态 ($num) 和回调方法(以 $i 作为参数)的对象:

As an alternative to @Charles's solution using closures, you can actually find an example in the comments on the documentation page. The idea is that you create an object with the desired state ($num) and the callback method (taking $i as an argument):

class LowerThanFilter {
        private $num;

        function __construct($num) {
                $this->num = $num;
        }

        function isLower($i) {
                return $i < $this->num;
        }
}

用法(演示):

$arr = array(7, 8, 9, 10, 11, 12, 13);
$matches = array_filter($arr, array(new LowerThanFilter(12), 'isLower'));
print_r($matches);

<小时>

作为旁注，您现在可以将 LowerThanFilter 替换为更通用的 NumericComparisonFilter 和诸如 isLower、isGreater 之类的方法>, isEqual 等等.只是一个想法 —和一个演示...

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As a sidenote, you can now replace LowerThanFilter with a more generic NumericComparisonFilter with methods like isLower, isGreater, isEqual etc. Just a thought — and a demo...

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