PHP 向多维数组的每个子数组添加元素 [英] PHP Add element to every sub array of multi dimension array

问题描述

我有一个看起来像这样的数组

I have an array that looks something like that

array(
     [0] => array(
               'id' => 1,
               'title' => 'title 1',
     ),
     [1] => array(
               'id' => 10,
               'title' => 'title 10',
     ),
     [2] => array(
               'id' => 11,
               'title' => 'title 11',
     ),
     [...]
);

我想向所有子数组添加一个元素.这与我要添加的元素相同.所以新数组看起来像:

I want to add an element to all the sub array. It's the same element i'm adding. so the new array will look like :

array(
     [0] => array(
               'id' => 1,
               'title' => 'title 1',
               'type'  => 'bag',
     ),
     [1] => array(
               'id' => 10,
               'title' => 'title 10',
               'type'  => 'bag',
     ),
     [2] => array(
               'id' => 11,
               'title' => 'title 11',
               'type'  => 'bag',
     ),
     [...]
);

有没有办法在第一个数组上不迭代?这将是一个大阵列.我正在寻找最快的方法.

Is there a way to do it without iterating on the the first array? It's gonna be a big array. I'm looking for the fastest way to do it.

推荐答案

无论人们希望通过使用 array_walk 获得什么速度，都会因函数开销而丢失.由于您在评论中指出该数组是 db 查询的结果，您可以通过添加 SELECT 'bag 简单地在结果集中包含 bag 值' AS 'type' 到您的 SQL 语句.

Whatever speed one might hope to gain by using array_walk, is lost with function overhead. Since you stated in your comments that the array is a result of a db query, you can simply include the bag value in your result set by adding SELECT 'bag' AS 'type' to your SQL statement.

$start = 0; $end = 0;

$orig = array(
    array('id' => 1,  'title' => 'title 1'),
    array('id' => 10, 'title' => 'title 10'),
    array('id' => 11, 'title' => 'title 11')
);

// A
$start = microtime(true);
for ($a=0; $a<1000; $a++) {
    $els1 = $orig;
    array_walk($els1, function(&$val, $key){$val['type'] = 'bag';});
}
$end = microtime(true);
echo 'A: ', $end - $start,  "<br />\n";

// B
$start = microtime(true);
for ($b=0; $b<1000; $b++) {
    $els2 = $orig;
    foreach ($els2 as &$el) {
        $el['type'] = 'bag';
    }
    unset($el);
}
$end = microtime(true);
echo 'B: ', $end - $start,  "<br />\n";

/* output:

A: 0.0076138973236084
B: 0.0047528743743896

A: 0.0075309276580811
B: 0.0045361518859863

A: 0.0075531005859375
B: 0.062379837036133

A: 0.0075340270996094
B: 0.0044951438903809

A: 0.0074868202209473
B: 0.0044751167297363

A: 0.0076088905334473
B: 0.0048189163208008

*/

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