laravel - php variable parsing

For example, now I have the variable $arr, which is an array

<code>$arr = [
    'news' => [
        'data' => [
            0 => [
                'title' => '名字',
                'content' => '内容'
            ],
        ],
    ],
];
</code>

Some frameworks or template engines have parsing functions. The value of title can be obtained through arr.news.data[0].title, and the value can be modified.

Then I want to know what its principle is, and how to use this expression efficiently, safely and simply to get and set the values ​​in the array?

What I can think of is to use text processing, but it should not be very safe and efficient. Ask the teacher for guidance.

Reply content:

For example, now I have the variable $arr, which is an array

<code>$arr = [
    'news' => [
        'data' => [
            0 => [
                'title' => '名字',
                'content' => '内容'
            ],
        ],
    ],
];
</code>

Some frameworks or template engines have parsing functions. The value of title can be obtained through arr.news.data[0].title, and the value can be modified.

Then I want to know what its principle is, and how to use this expression efficiently, safely and simply to get and set the values ​​in the array?

What I can think of is to use text processing, but it should not be very safe and efficient. Ask the teacher for guidance.

Most template engines are processed in a pre-compiled manner, that is, the input template data will be converted into standard PHP statements such as variables, loops, conditions and other symbols, and then executed.

In addition, these frameworks or template engines are all open source. If you have time to ask people here, you will already understand if you look at the code yourself.

Let me find you a code.

<code> public static function getValue($array, $key, $default = null)
    {
        if ($key instanceof \Closure) {
            return $key($array, $default);
        }

        if (is_array($key)) {
            $lastKey = array_pop($key);
            foreach ($key as $keyPart) {
                $array = static::getValue($array, $keyPart);
            }
            $key = $lastKey;
        }

        if (is_array($array) && (isset($array[$key]) || array_key_exists($key, $array)) ) {
            return $array[$key];
        }

        if (($pos = strrpos($key, '.')) !== false) {
            $array = static::getValue($array, substr($key, 0, $pos), $default);
            $key = substr($key, $pos + 1);
        }

        if (is_object($array)) {
            // this is expected to fail if the property does not exist, or __get() is not implemented
            // it is not reliably possible to check whether a property is accessable beforehand
            return $array->$key;
        } elseif (is_array($array)) {
            return (isset($array[$key]) || array_key_exists($key, $array)) ? $array[$key] : $default;
        } else {
            return $default;
        }
    }</code>