php5.5新數組函數array

PHP5.5發布了，其中增加了一個新的數組函數array_column，感覺不錯的！但是低版本PHP要使用，得自己實現：
參考地址：https://wiki.php.net/rfc/array_column

 

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if(!function_exists('array_column')){    function array_column($input, $columnKey, $indexKey=null){        $columnKeyIsNumber      = (is_numeric($columnKey)) ? true : false;        $indexKeyIsNull         = (is_null($indexKey)) ? true : false;        $indexKeyIsNumber       = (is_numeric($indexKey)) ? true : false;        $result                 = array();        foreach((array)$input as $key=>$row){            if($columnKeyIsNumber){                $tmp            = array_slice($row, $columnKey, 1);                $tmp            = (is_array($tmp) && !empty($tmp)) ? current($tmp) : null;            }else{                $tmp            = isset($row[$columnKey]) ? $row[$columnKey] : null;            }            if(!$indexKeyIsNull){                if($indexKeyIsNumber){                    $key        = array_slice($row, $indexKey, 1);                    $key        = (is_array($key) && !empty($key)) ? current($key) : null;                    $key        = is_null($key) ? 0 : $key;                }else{                    $key        = isset($row[$indexKey]) ? $row[$indexKey] : 0;                }            }            $result[$key]       = $tmp;        }        return $result;    }} // 使用例子$records = array(    array(        'id' => 2135,        'first_name' => 'John',        'last_name' => 'Doe'    ),    array(        'id' => 3245,        'first_name' => 'Sally',        'last_name' => 'Smith'    ),    array(        'id' => 5342,        'first_name' => 'Jane',        'last_name' => 'Jones'    ),    array(        'id' => 5623,        'first_name' => 'Peter',        'last_name' => 'Doe'    ));$firstNames = array_column($records, 'first_name');print_r($firstNames);/*Array(    [0] => John    [1] => Sally    [2] => Jane    [3] => Peter)*/ $records = array(    array(1, 'John', 'Doe'),    array(2, 'Sally', 'Smith'),    array(3, 'Jane', 'Jones'));$lastNames = array_column($records, 2);print_r($lastNames);/*Array(    [0] => Doe    [1] => Smith    [2] => Jones)*/ $mismatchedColumns = array(    array(        'a' => 'foo',        'b' => 'bar',        'e' => 'baz'    ),    array(        'a' => 'qux',        'c' => 'quux',        'd' => 'corge'    ),    array(        'a' => 'grault',        'b' => 'garply',        'e' => 'waldo'    ),);$foo = array_column($mismatchedColumns, 'a', 'b');print_r($foo);/*Array(    [bar] => foo    [0] => qux    [garply] => grault)*/