PHP step hole array access

One 、 Parse array elements in double quotation string
error ：

$array = [
    'name' => 'Tom'
];
echo " Array elements ：$array['name']";

correct ：

$array = [
    'name' => 'Tom'
];
echo " Array elements ：{
      $array['name']}";

Two 、 Get the reference of the array element
error ：

$normal_array = [
    'array1' => [
        'array2' => 1
    ]
];
$c = &($normal_array['array1']); //  Start reporting errors here ,& Later cannot be connected with () The values in correspond to , Unless () Return for reference , For example, the return value of a reference function 
$c['test'] = 3;
var_export($normal_array);

correct ：

$normal_array = [
    'array1' => [
        'array2' => 1
    ]
];
$c = &$normal_array['array1'];
$c['test'] = 3; //  Reference assignment succeeded 
var_export($normal_array);