How to reffer dynamically to a php ARRAY variable(s)?

Question

Everybody knows that you can access a variable in PHP using this: ${\'varName\'}. But when you need to get/set a variable witch is part of an array, why doesn\'t it work ? Suppo

Answer 1

You could do something like this, but it would be a really bad idea. Sorry Col. ;)

<?php
$mA = array();
$mVN = "mA['m1']['m2']['m3']";
eval('$'. $mVN . ' = "new value";');
print_r($mA);
?>

Answer 2

Shouldn't it work ?

No.

Everybody knows that you can access a variable in PHP using this: ${'varName'}.

Yes. Yet everybody knows that's lame.

How to refer dynamically to a php array variable(s)?

having array of ('my1','my11','my111') you can refer to any particular array member using merely a loop.

Answer 3

I recommend you not to use dynamic variables like ${$var}. What you want is modifying a multi-dimensional associative array according to a path of keys.

<?php
$myArray = array(...); // multi-dimensional array
$myVarPath = array('my1', 'my11', 'my111');
setValueFromPath($myArray, $myVarPath);

function getValueFromPath($arr, $path)
{
    // todo: add checks on $path
    $dest = $arr;
    $finalKey = array_pop($path);
    foreach ($path as $key) {
        $dest = $dest[$key];
    }
    return $dest[$finalKey];
}

function setValueFromPath(&$arr, $path, $value)
{
    // we need references as we will modify the first parameter
    $dest = &$arr;
    $finalKey = array_pop($path);
    foreach ($path as $key) {
        $dest = &$dest[$key];
    }
    $dest[$finalKey] = $value;
}

This is a procedural example to keep it simple. You may want to put your hierarchical array and this functions inside a class.