Yii2.0 ArrayHelper::map() usage method

Construct a mapping (in the form of key-value) from a multidimensional array or array

The mapping relationship is set by specifying the corresponding key value or attribute name through the "$from" and "$to" parameters.

Of course, you can also further group mapping based on the grouping field "$group".

For example:

$array = [ ['id' => '123', 'name' => 'aaa', 'class' => 'x'], ['id' => '124', 'name' => 'bbb', 'class' => 'x'], ['id' => '345', 'name' => 'ccc', 'class' => 'y'], ];

The above array executes the following method

还可以添加第四个参数 $result = ArrayHelper::map($array, 'id', 'name', 'class');

The result is

[ 'x' => [ '123' => 'aaa', '124' => 'bbb', ], 'y' => [ '345' => 'ccc', ], ]

The following is the detailed code of the map method

/** * @paramarray $array * @param string|Closure $from * @param string|Closure $to * @param string|Closure $group * @return array */ public static function map($array, $from, $to, $group = null) { $result = []; foreach ($array as $element) { $key = static:: getValue($element, $from); $value = static:: getValue($element, $to); if ($group !== null) { $result[ static:: getValue($element, $group)][$key] = $value; } else { $result[$key] = $value; } } return $result; }