在创建匿名 PHP 函数期间呈现变量 [英] Render a variable during creation of anonymous PHP function

问题描述

我正在尝试使用匿名函数获得一个简单的排序函数.升序和降序排序各一个.

I'm trying to get a simple sort function going using anonymous functions. One each for asc and desc sorting.

是否可以在创建函数时立即呈现 $sortBy 变量，但仍然传递了 $x 和 $y在什么时候调用?我希望能够在创建这些时动态传入一个键.

Is it possible to render the $sortBy variable right away when the function is created, but still have $x and $y passed in when called later? I want to be able to dynamically pass in a key when creating these.

$sortBy = 'some_key';

// descending
$sort['desc'] = function($x, $y) {
  if($x['data'][$sortBy] == $y['data'][$sortBy])
    return 0;

  return ($x['data'][$sortBy] > $y['data'][$sortBy]) ? -1 : 1;
};

uasort($arrayToSort, $sort[$order]);

我将此数组作为参数传递给 uasort().

I'm passing this array as a param to uasort().

推荐答案

您可以使用 在封闭范围内传递变量use 关键字(示例 #3 闭包和范围):

You can pass a variable in enclosing scope using the use keyword (Example #3 Closures and scoping):

$sortBy = 'some_key';

$sort['desc'] = function($x, $y) use ($sortBy) {
    // implementation
};

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