本机php函数将单维数组转换为二维数组

I want to turn plain array into two dimensional array. I can do it with a code below but is there native PHP function to handle it. I went through the manual and wen but didn't see anything.

Thanks

$array = array('a', 'b');

Should be converted into:

$array = array('a'=>'a', 'b'=>'b');

I don't want to use this if there is a simple function:

foreach($array as &$value)
{
    $new[$value] = $value;
}

You can use array_combine(), which combines (suprisingly enough) an array of keys and an array of values into a single array.

$array = array_combine($array, $array);