Extract item from multi-dimensional array from custom depth - php

Question

I have multidimensional array like this:
$obj = array(
"a" => array(
"aa" => array(
"aaa" => 1
),
"bb" => 2,
),
"b" => array(
"ba" => 3,
"bb" => 4,
),
"c" => array(
"ca" => 5,
"cb" => 6,
),
);
I can not figured out a neatest way, e.g. custom-depth function, to extract item at specific location with arguments to function (or array of key names). For example:
echo $obj[someFunc("a", "aa", "aaa")];
... should return 1.
print_r($obj[someFunc("a")]);
... should return:
Array
(
[aa] => Array
(
[aaa] => 1
)
[bb] => 2
)
What is the best way to accomplished this with php7 features?

Answer 1

Since PHP 5.6, ["Variadic functions"][1] have existed. These provide us with a nice simple to read way to collect arguments used in calling a function into a single array. For example:
function getValue(...$parts) {
var_dump($parts);
}
getValue('test', 'part');
Will output:
array(2) {
[0]=>
string(4) "test"
[1]=>
string(4) "part"
}
This was all possible before using built-in functions to get the parameters, but this is more readable.
You could also be a little more explicit with the argument types, but I'll leave that for you to figure out if necessary.
You next major challenge is to loop through the arguments. Something like this will produce the value that you desire.
function getValue(...$parts) {
$returnValue = $obj;
foreach ($parts as $part) {
$returnValue = $obj[$part];
}
return $returnValue;
}
However, this is rather crude code and will error when you try calling it to access non-existent parts. Have a play and fix those bits.
[1]: https://www.php.net/manual/en/functions.arguments.php#functions.variable-arg-list