使用PHP中的特定键格式获取数组值

Question

Consider following array and function:

$array = [
  'key' => [
    'key_2' => [
       'key_3' => 'Value 3'
    ]
  ],
];

function get_value( $key ) {
  echo $array . $key;
}

now I want to call the function like this:

get_value( 'key[key_2][key_3]' );

It gives error which is natural.

Possible to write get_value function in a way that it understands 'key[key_2][key_3]' and gives the value?

Answer 1

Since the input string seems to be used quite loosely I'm going to assume this can be manipulated to something easier to use.

Here I explode the keys and loop them and dig in the array til I'm out of keys.
Mind that the return can be either array or string/int/float/bool

function get_value($array, $key ) {
    $keys = explode(",", $key);
    Foreach($keys as $k){
        $array = $array[$k];
    }
    Return $array;
}

Var_dump(get_value($array, 'key,key_2,key_3' ));

https://3v4l.org/mnvOs

You can use the input string you have with a str_replace.
But I don't understand the logic in it. They are all keys, but only the second and third have [] around them.

See here for str_replace example: https://3v4l.org/BObTk

Answer 2

You cannot pass the argument to the function as mentioned in your code. If you want to print all the values or print a value of a specific key, you'll have to pass the key to the function as a string.

Consider the example below:

function get_value( $key = null ) {
    $array = [
       'key' => [
          'key_2' => array(
             'key_3' => 'Value 3'
          )
       ],
    ];

    $keys = explode('|', $key);
    $result = '';
    foreach ($keys as $key) {
        if (empty($result)) {
            $result = $array[$key];       
        } else {
            $result = $result[$key];     
        }
    }

    echo $result;
}

Now if you pass get_value('key|key_2|key_3'), this will work.

Also the scope in php is not as same as in javascript. you cannot access the outside function variables inside a function. Refer this article for more info on scopes Variable Scopes

Hope this helps.