php - 根据给定的字符串对数组进行排序

Question

我有一个来自数据库的结果集的 php 数组。

由于我不太熟悉 mySQL 排序，我想根据特定字符串“madhapur”对结果集进行排序

$arr=array(    
    array("name" => 'madhapur',"population" =>'1000'),
    array("name" => 'jubiliee hills',"population" =>'800'),
    array("name" => 'madhapur',"population" =>'900'),
    array("name" => 'adikmet',"population" =>'200'),
    array("name" => 'sr nagar',"population" =>'3000'),
    array("name" => 'jubilee hills',"population" =>'1200'),
    array("name" => 'madhapur',"population" =>'1000')   
    );

我期待的结果如下

$arr=array(
array("name" => 'madhapur',"population" =>'1000'),
array("name" => 'madhapur',"population" =>'1000'),
array("name" => 'madhapur',"population" =>'900'),
array("name" => 'adikmet',"population" =>'200'),
array("name" => 'jubilee hills',"population" =>'1200'),
array("name" => 'jubiliee hills',"population" =>'800'),
array("name" => 'sr nagar',"population" =>'3000'),
);

我尝试使用 usort，但它们都用于降序或升序排序。

function sortByName($a,$b){
         return $b['name'] - $a['name'];
    }
usort($arr,'sortByName');

Answer 1

在您的sql中按名称和人口进行第一个排序，因为您的示例似乎显示了以这种方式排序的所有内容，除了提升到顶部的特定名称(madhapur)之外

(注意DB类是一个例子，因为我不知道你使用什么数据库访问方法):

$arr = DB::Query("SELECT name, population 
                  FROM tablename 
                  ORDER BY name ASC, population DESC");

然后你可以迭代数组，并将具有你想要的名称的元素放在开头:

function nameAtFront($arr, $name){

    $copy = $arr;
    $total = count($arr);
    while($total--){
        if($copy[$total]['name']==$name){
            unset($arr[$total]);
            array_unshift($arr, $copy[$total]);
        }
    }
    return $arr;
}
$out = nameAtFront($arr, 'madhapur');
var_dump($out);