在Jakub的出色回答的基础上，这里有一个更通用的搜索，将允许指定键(不仅仅是uid):

function searcharray($value, $key, $array) {
   foreach ($array as $k => $val) {
       if ($val[$key] == $value) {
           return $k;
       }
   }
   return null;
}

用法:$results = searcharray('searchvalue'， searchkey， $array);

我修改了下面的一个例子，描述函数array_search。函数searchItemsByKey返回多维数组(N层)中通过$key返回的所有值。也许，它会对某人有用。例子:

 $arr = array(
     'XXX'=>array(
               'YYY'=> array(
                    'AAA'=> array(
                          'keyN' =>'value1'
                   )
               ),
              'ZZZ'=> array(
                    'BBB'=> array(
                          'keyN' => 'value2'
                   )
               )
              //.....
           )
);


$result = searchItemsByKey($arr,'keyN');

print '<pre>';
print_r($result);
print '<pre>';
// OUTPUT
Array
(
  [0] => value1
  [1] => value2
)

函数代码:

function searchItemsByKey($array, $key)
{
   $results = array();

  if (is_array($array))
  {
    if (isset($array[$key]) && key($array)==$key)
        $results[] = $array[$key];

    foreach ($array as $sub_array)
        $results = array_merge($results, searchItemsByKey($sub_array, $key));
  }

 return  $results;
}

还没有人使用过array_reduce，所以我想添加这个方法…

$find_by_uid = '100';
$is_in_array = array_reduce($userdb, function($carry, $user) use ($find_by_uid){
    return $carry ? $carry : $user['uid'] === $find_by_uid;
}); 
// Returns true

与array_search()相比，可以更好地控制'search'逻辑。

注意，我在这里使用了严格的等式，但您可以选择不同的比较逻辑。$carry意味着比较需要为真一次，最终结果将为真。

我知道这个问题已经回答了，但我在代码中使用了这个问题并对其进行了扩展，这样就不需要只根据uid进行搜索了。我只是想把它分享给其他可能需要这个功能的人。

这是我的例子，请记住这是我的第一个答案。我去掉了参数数组，因为我只需要搜索一个特定的数组，但是您可以很容易地将它添加进去。我想要搜索的不仅仅是uid。

此外，在我的情况下，由于其他字段的搜索结果可能不是唯一的，可能有多个键要返回。

 /**
     * @param array multidimensional 
     * @param string value to search for, ie a specific field name like name_first
     * @param string associative key to find it in, ie field_name
     * 
     * @return array keys.
     */
     function search_revisions($dataArray, $search_value, $key_to_search) {
        // This function will search the revisions for a certain value
        // related to the associative key you are looking for.
        $keys = array();
        foreach ($dataArray as $key => $cur_value) {
            if ($cur_value[$key_to_search] == $search_value) {
                $keys[] = $key;
            }
        }
        return $keys;
    }

后来，我写了这个，以允许我搜索另一个值和关联键。因此，我的第一个示例允许您在任何特定的关联键中搜索值，并返回所有匹配的值。

第二个例子显示了在某个关联键(first_name)中找到一个值('Taylor')，在另一个关联键(hired)中找到另一个值(true)，并返回所有匹配(名字为'Taylor'并且被雇用的人的键)。

/**
 * @param array multidimensional 
 * @param string $search_value The value to search for, ie a specific 'Taylor'
 * @param string $key_to_search The associative key to find it in, ie first_name
 * @param string $other_matching_key The associative key to find in the matches for employed
 * @param string $other_matching_value The value to find in that matching associative key, ie true
 * 
 * @return array keys, ie all the people with the first name 'Taylor' that are employed.
 */
 function search_revisions($dataArray, $search_value, $key_to_search, $other_matching_value = null, $other_matching_key = null) {
    // This function will search the revisions for a certain value
    // related to the associative key you are looking for.
    $keys = array();
    foreach ($dataArray as $key => $cur_value) {
        if ($cur_value[$key_to_search] == $search_value) {
            if (isset($other_matching_key) && isset($other_matching_value)) {
                if ($cur_value[$other_matching_key] == $other_matching_value) {
                    $keys[] = $key;
                }
            } else {
                // I must keep in mind that some searches may have multiple
                // matches and others would not, so leave it open with no continues.
                $keys[] = $key;
            }
        }
    }
    return $keys;
}

函数的使用

$data = array(
    array(
        'cust_group' => 6,
        'price' => 13.21,
        'price_qty' => 5
    ),
    array(
        'cust_group' => 8,
        'price' => 15.25,
        'price_qty' => 4
    ),
    array(
        'cust_group' => 8,
        'price' => 12.75,
        'price_qty' => 10
    )
);

$findKey = search_revisions($data,'8', 'cust_group', '10', 'price_qty');
print_r($findKey);

结果

Array ( [0] => 2 ) 

for( $i =0; $i < sizeof($allUsers); $i++)
    {   
    $NEEDLE1='firstname';
    $NEEDLE2='emailAddress';
    $sterm='Tofind';
     if(isset($allUsers[$i][$NEEDLE1]) && isset($allUsers[$i][$NEEDLE2])
        {
            $Fname= $allUsers[$i][$NEEDLE1];
            $Lname= $allUsers[$i][$NEEDLE2];

            $pos1 = stripos($Fname, $sterm);
            $pos2=stripos($Lname, $sterm);//not case sensitive 

            if($pos1 !== false ||$pos2 !== false)
            {$resultsMatched[] =$allUsers[$i];}
            else
            {   continue;}              
        }

}
Print_r($resultsMatched); //will give array for matched values even partially matched

在上述代码的帮助下，可以从2D数组中的任何列中找到任何(部分匹配)数据，因此可以根据需要找到用户id。

如果问题，即。

$a = [
     [
       "_id" => "5a96933414d48831a41901f2",
       "discount_amount" => 3.29,
       "discount_id" => "5a92656a14d488570c2c44a2",
     ],
     [
       "_id" => "5a9790fd14d48879cf16a9e8",
       "discount_amount" => 4.53,
       "discount_id" => "5a9265b914d488548513b122",
     ],
     [
       "_id" => "5a98083614d488191304b6c3",
       "discount_amount" => 15.24,
       "discount_id" => "5a92806a14d48858ff5c2ec3",
     ],
     [
       "_id" => "5a982a4914d48824721eafe3",
       "discount_amount" => 45.74,
       "discount_id" => "5a928ce414d488609e73b443",
     ],
    [
       "_id" => "5a982a4914d48824721eafe55",
       "discount_amount" => 10.26,
       "discount_id" => "5a928ce414d488609e73b443",
     ],
   ];

岁:

function searchForId($id, $array) {
    $did=0;
    $dia=0;
   foreach ($array as $key => $val) {
       if ($val['discount_id'] === $id) {
           $dia +=$val['discount_amount'];
           $did++;
       }
   }
    if($dia != '') {
        echo $dia;
        var_dump($did);
    }
   return null;
};
print_r(searchForId('5a928ce414d488609e73b443',$a));