Check if a “run-time” multidimensional array key exists [duplicate]

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Check if a “run-time” multidimensional array key exists

Hi,

I have a multidimensional array. I need a function that checks if a specified key exists and if not set the value.

Let's take this array

$config['lib']['template']['engine'] = false;

A function should not update the value to true when i call with:

checkAndSetKey('lib template engine',true);
//> Checks if isset $config['lib']['template']['engine'] and if not isset $config['lib']['template']['engine'] = true;

Note that my array isn't only 3 dimensional. It should be able to check and set even with only 1 dimension:

checkAndSetKey('genericSetting',true);
//> In this considering there isn't any $c['generic开发者_运维百科Setting'] the function set the key to true;

At the moment I am using an awful eval code, I would like to hear suggest :)

To dynamically check if the key exists it could be used this code:

$array = $config;
$keys=explode(' ',$argument1);

foreach($keys as $v) { 

    if (!array_key_exists($v,$array)) {
        //> [todo!] the current key doens't exist now we should set the value
    }

    $array = &$array[$v];
}

---

With slight modification (passing array as reference argument) this should work:

function checkAndSetKey(&$arr, $keys, $value){
    $moreKeys = strpos($keys,' ');
    if($moreKeys !== FALSE){
        $currentKey = substr($keys, 0, $moreKeys);
        $keys = substr($keys, $moreKeys+1);

        if(!isset($arr[$currentKey]) || !is_array($arr[$currentKey]))
            $arr[$currentKey] = array();

        return checkAndSetKey($arr[$currentKey], $keys, $value);
    }else{
        $currentKey = $keys;
        if(!isset($arr[$currentKey]))
            $arr[$currentKey] = $value;

        return $arr[$currentKey];
    }
}

---

LOL actually this was just one line of code added there =/
For a moment the references confused me a bit.

Here the code :

function _c($key,$value) {
    global $c;

    $array = &$c;
    $keys = explode(' ',$key);

    $setValue = false;
    for($i=0;$i<count($keys);$i++) { 
        $v = $keys[$i];

        //> If setValue is already = true we don't need to check it again
        if (!$setValue && !array_key_exists($v,$array))
            $setValue = true;

        $array = &$array[$v];
    }

    if ($setValue)
        $array = $value;
}

//> Usage _c('lib template engine',true);

---

First off, its worth bearing in mind that PHP arrays are NOT multi-dimensional, they are hierarchical.

PHP already provides a method for testing if an array key exists. Wrapping this in your own code should be trivial, particularly if the number of levels in the array is fixed:

function checkAndSetKey(&$arr, $path, $default)
{
   $path=explode(' ', $path);

   if (!is_array($arr[$path[0]])) { // lib
         $arr[$path[0]]=array();
   }
   if (!is_array($arr[$path[0]][$path[1]])) { // template
         $arr[$path[0]][$path[1]]=array();
   }
   if (!array_key_exists($path[2],$arr[$path[0]][$path[1]])) { // engine
         $arr[$path[0]][$path[1]][$path[2]]=$default;
   }
   return $arr[$path[0]][$path[1]][$path[2]];
}

With a bit of though the method above could be adapted using recursion to handle an arbitrary number of levels.