php - PHP：如何通过键对数组进行分组？

Question

我有一个uploads看起来像这样的数组：

$uploads[0] = array('type' => 'upload', 'label' => 'blah');
$uploads[1] = array('type' => 'upload', 'label' => 'blah');
$uploads[2] = array('type' => 'upload', 'label' => 'blah');
$uploads[3] = array('type' => 'upload', 'label' => 'foobar');

我想创建这个数组：

$upload_fields = array(
   'blah' => array(
               array('type' => 'upload', 'label' => 'blah')
               array('type' => 'upload', 'label' => 'blah')
               array('type' => 'upload', 'label' => 'blah')
    ),
   'foobar' => array(
               array('type' => 'upload', 'label' => 'foobar')    
    )
);

基本上我想根据它们的标签对数组进行分组。要分组的数组是动态的，否则我可以执行以下操作：

$array_group_1 = array();
$array_group_2 = array();

foreach($uploads as $upload) {
    if($upload['label'] == 'blah') {
        array_push($array_group_1, $upload);
    }  else {
        array_push($array_group_2, $upload);        
    }
}

$upload_fields = array(
    'blah' => $array_group_1,
    'foobar' => $array_group_2
);

但是由于键是动态的，我该如何实现呢？

Answer 1

这就是我想出的：

$uploads[0] = array('type' => 'upload', 'label' => 'blah');
$uploads[1] = array('type' => 'upload', 'label' => 'blah');
$uploads[2] = array('type' => 'upload', 'label' => 'blah');
$uploads[3] = array('type' => 'upload', 'label' => 'foobar');

foreach($uploads as $u){
    $upload_fields[$u['label']][] = $u;
}

echo '<pre>',print_r($upload_fields),'</pre>';

Answer 2

您可以使用许多奇异的数组函数来获取动态数组键和值http://www.php.net/manual/en/ref.array.php

下面的代码可以通过压缩那个if else语句来优化，但是我这样留着是为了让例子很清楚

$uploads[0] = array('type' => 'upload', 'label' => 'blah');
$uploads[1] = array('type' => 'upload', 'label' => 'blah');
$uploads[2] = array('type' => 'upload', 'label' => 'blah');
$uploads[3] = array('type' => 'upload', 'label' => 'foobar');

$result = array();

foreach($uploads AS $upload)
{
    if(array_key_exists($upload['label'], $result))
    {
        array_push($result[$upload['label']], $upload);
    }
    else
    {
        $result[$upload['label']] = array();
        array_push($result[$upload['label']], $upload);
    }
}

var_dump($result);

Answer 3

$temp = array();
$final_array = array();

foreach($uploads as $upload){
    if(!in_array($upload['label'], $temp)){
        $final_array[$upload['label']] = array('type' => upload['type'], 'label' => $temp);
        $temp[] = $upload['label'];
    }
}

var_dump($final_array);