排序和破坏多维数组

Question

我有一个多维数组(实际数组可以有500多个成员)

$marr = array( array("s_id" => 1, 1.25 , 15),
               array("s_id" => 2, 0.75 , 25),
               array("s_id" => 1, 1.15 , 7) 
             ); 

我试图将其分解成一个由成员数组的s_id值分组/索引的数组

$sarr        = array(
                    1 => array(
                                 array("s_id" => 1, 1.25 , 15),
                                 array("s_id" => 1, 1.15 , 7) 
                                 ),
                    2 => array(
                                 array("s_id" => 2, 0.75 , 25)
                                 )
                    );

是否有一个内置的函数在php中做到这一点或一些最佳实践的方式做到这一点?

Answer 1

没有内置函数可以提供此结果。相反，您需要遍历数组，并检查与s_id值匹配的键是否已经存在。如果它没有在那个键处创建一个新的数组

$marr = array( array("s_id" => 1, 1.25 , 15),
               array("s_id" => 2, 0.75 , 25),
               array("s_id" => 1, 1.15 , 7) 
             ); 
// Holds the whole output
$output = array();
// Looping over the original array
foreach ($marr as $subarr) {
  // Check if the output array already has the s_id as a key
  if (!isset($output[$subarr['s_id']])) {
    // Initialize it
    $output[$subarr['s_id']] = array();
  }
  // Then append the current sub-array to the s_id array key
  $output[$subarr['s_id']][] = $subarr;
}
// Then call ksort() on the output array
// to sort the s_id keys in ascending order
ksort($output);

http://codepad.viper - 7. - com/ssbral

打印:

Array
(
    [1] => Array
        (
            [0] => Array
                (
                    [s_id] => 1
                    [0] => 1.25
                    [1] => 15
                )
            [1] => Array
                (
                    [s_id] => 1
                    [0] => 1.15
                    [1] => 7
                )
        )
    [2] => Array
        (
            [0] => Array
                (
                    [s_id] => 2
                    [0] => 0.75
                    [1] => 25
                )
        )
)