Question

I have a person array, with a key ‘n’ for name. The value for ‘n’ is an array, with key ‘l’ (short for ‘last’) having the value I want to get at, the last name.

For curious programming reasons, I have “address” of the last name as a string.

How do I do this?
I’ve tried eval, among others.

SORRY I wasn’t being clear!!

What I want is to use the variable $test to get it.

E.g. something like:

$person[$test]

(which obviously doesn’t work, but what does?)

$test won’t always be ‘two deep’. E.g. sometimes it will be ['a']['residential']['street']

<?php

    $test = "['n']['l']";

    echo "I've got a string with the array index ".$test. "\n";

    $person = array("n"=>array('l'=>'SMITH'));

    echo 'the array, $person, is this: '."\n";
    print_r($person);

    echo "What I want is ".$person['n']['l']. "\n";
    ?>

Output:

I've got a string with the array index ['n']['l']
the array, $person, is this: 

    Array
    (
        [n] => Array
            (
                [l] => SMITH
            )

    )

What I want is SMITH

Answer 1

You pretty much have only two options:

Using eval:

function IAmEvilSoYouShouldNotCallMe($array, $key) {
    return eval('return $array' . $key . ';');
}

echo IAmEvilSoYouShouldNotCallMe(
    array("n"=>array('l'=>'SMITH')),
    "['n']['l']"
);

Or string parsing:

function helper($array, $key) {
    $keys = array_map(function ($val) {
        return trim($val, "]['");
    }, explode('][', $key));    

    while ($key = array_shift($keys)) {
        if (isset($array[$key])) {
            $array = $array[$key];
            continue;
        }

        return null;
    }

    return $array;
}

echo helper(
    array("n"=>array('l'=>'SMITH')),
    "['n']['l']"
);

Both output:

SMITH