php中去除一维数组中的数字索引

$arr = ['0' => '张三', 1 => '李四', '2' => '王五', 'age' => 60, 'name' => [3 => '赵六']];
$arr2 = array_filter($arr, 'is_string', ARRAY_FILTER_USE_KEY);
var_dump($arr2);

结果如下图：