use strings to access (potentially large) multidimensional arrays

Question

I am having trouble figuring out a way to simply parse a string input and find the correct location within a multidimensional array.

I am hoping for one or two lines

Answer 1

Considering $vars being your variables you would like to get one['one-one'] or two['two-two']['more'] from (Demo):

$vars = function($str) use ($vars)
{
    $c = function($v, $w) {return $w ? $v[$w] : $v;};
    return array_reduce(preg_split('~\[\'|\'\]~', $str), $c, $vars);
};
echo $vars("one['one-one']"); # hello
echo $vars("two['two-two']['more']"); # tea-time!

This is lexing the string into key tokens and then traverse the $vars array on the keyed values while the $vars array has been turned into a function.

---

Older Stuff:

Overload the array with a function that just eval's:

$vars = array(
    'one' => array(
        'one-one' => "hello",
        'one-two' => "goodbye"
    ),
    'two' => array(
        'two-one' => "foo",
        'two-two' => "bar"
    )
);

$vars = function($str) use ($vars)
{
    return eval('return $vars'.$str.';');
};

echo $vars("['one']['one-two']"); # goodbye

If you're not a fan of eval, change the implementation:

$vars = function($str) use ($vars)
{
    $r = preg_match_all('~\[\'([a-z-]+)\']~', $str, $keys);
    $var = $vars;
    foreach($keys[1] as $key)
        $var = $var[$key];
    return $var;
};
echo $vars("['one']['one-two']"); # goodbye

Answer 2

Kohana has a nice Config class which alows something like this:

echo Config::get("two.two-two");

You can check it out here: http://kohanaframework.org/3.1/guide/api/Config

Answer 3

How about

$vars = array(
    'one' => array(
        'one-one' => "hello",
        'one-two' => "goodbye"
    ),
    'two' => array(
        'two-one' => "foo",
        'two-two' => "bar"
    )
);

function get( $string, $vars )
{
    $keys = explode( '][', substr( $string, 1, -1 ) );
    foreach( $keys as $key ) {
        $vars = $vars[$key];
    }
    return $vars;
}

echo get( '[two][two-one]', $vars );

Answer 4

For one, you've not got a $var in your get() function. $var was defined outside the function, and PHP scoping rules do not make "higher" vars visible in lower scopes unless explictly made global in the lower scope:

function get($string) {
   global $vars;
   eval('$x = $vars' . $string);
   return $x;
}

get("['two']['two-two']");

might work, but this isn't tested, and using eval is almost always a very bad idea.