php - Convert a string into a nested array

Question

I would like to dynamically set/get array's elements with a string as element keys.
So I'm looking for the good way to convert a string into a multiple keys array.
I reach the expected result with that piece of ugly code, which I'm not proud of:

function arrayElementSet($str, $value, array &$array)
{
    $arrayStr = "['".preg_replace('/\./', "']['", $str)."']";
    eval('$array'.$arrayStr.'="'.$value.'";');
}

function arrayElementGet($str, array &$array)
{
    $arrayStr = "['".preg_replace('/\./', "']['", $str)."']";
    eval('$ret=$array'.$arrayStr.';');
    return $ret;
}

$array = array();
arrayElementSet('d0.d1.d2.d4', 'bar', $array);
$wantedElement = arrayElementGet('d0.d1.d2', $array);
print_r($array);
/*
wantedElement looks like:
Array
(
    [d4] => bar
)
$array looks like:
Array
(
    [d0] => Array
        (
            [d1] => Array
                (
                    [d2] => Array
                        (
                            [d4] => bar
                        )
                )
        )
)
*/

But that's pretty ugly, plus I would like to avoid the eval() function.
I'm not particularly attached to an array solution, if there is a nice solution with an object or whatever, I'll take it.

---

EDIT:

Just to know. Two Helper Functions from Laravel comes out of the box (array_get and array_set):

• http://laravel.com/api/source-function-array_get.html#_array_get
• http://laravel.com/api/source-function-array_get.html#_array_set

Answer 1

拆分和遍历：

<?php
function arrayElementSet($str, $value, array &$array, $delimiter = '.') {
  $parent =& $array;
  foreach (explode($delimiter, $str) as $key) {
    if (!array_key_exists($key, $parent)) {
      $parent[$key] = array();
    }  

    $parent =& $parent[$key];
  }

  $parent = $value;
}

function arrayElementGet($str, array &$array, $delimiter = '.') {
  $parent =& $array;
  foreach (explode($delimiter, $str) as $key) {
    if (!array_key_exists($key, $parent)) {
      return null;
    }  

    $parent =& $parent[$key];
  }

  return $parent;
}

$array = array();
arrayElementSet('d0.d1.d2.d4', 'bar', $array);
$wantedElement = arrayElementGet('d0.d1.d2', $array);

print_r($array);
print_r($wantedElement);

http://codepad.viper-7.com/maNmOT

Answer 2

function insertElementToArray($path, $value, &$array){
    if (!is_array($path)){
        $path = explode('.', $path);
    }
    if (($cnt = count($path)) == 0) return true;

    $defValue = (array_key_exists($key = array_shift($path), $array)) 
        ? $array[$key] 
        : array();
    $array[$key] = ($cnt == 1) ? $value : $defValue;
    insertElementToArray($path, $value, $array[$key]);
}

使用：

insertElementToArray('d0.d1.d2.d4', 'bar', $array);