动态数组键添加

Here is my precode...

$keys = array('a', 'b', 'c', 'd');
$number = 10;

And here is my code...

eval('$array[\''.implode('\'][\'',$keys).'\'] = $number;');

Using this, I get the following result...

Array (
    [a] => Array
        (
            [b] => Array
                (
                    [c] => Array
                        (
                            [d] => 10
                        )
                )
        )
)

Now, the problem is that this is the exact result I want, but I don't want to use eval().

As input to my code, I have a list of keys and a number. The number should be set to the value of the keys array being used to generate child-based keys for a certain array $array.

Is there a different way that I can achieve this? I don't want to overwrite the keys/numbers with new values as the code works - eval() preserves this already, so my new code should do the same.

Here is a full code example showing how it would work. Whats important is that you use a reference to the array so you can modify it:

<?php
    $keys = array('a', 'b', 'c', 'd'); 
    $number = 10;

    $org_array = array(
        "a" => "string",
        "z" => array( "k" => false)
      );

    function write_to_array(&$array, $keys, $number){
      $key = array_shift($keys);
      if(!is_array($array[$key])) $array[$key] = array();
      if(!empty($keys)){
        write_to_array($array[$key], $keys, $number);
      } else {
        $array[$key] = $number;
      }
    }

    write_to_array($org_array, $keys, $number);

    print_r($org_array);
?>

Please note that the code below (which you evaluate) will generate a warning, and will therefore not work on projects with error reporting up to the max:

$array = array();
$array['a']['b'] = 42; // $array['a'] is not an array... yet

Since you're using PHP 5, you can work with references to manipulate your array while traversing the branch of your tree that you wish to modify.

$current = & $array;

foreach ($keys as $key):

  if (!isset($current[$key]) || !is_array($current[$key]))
    $current[$key] = array();

  $current = & $current[$key];

endforeach;

$current = $value;

Edit: corrected for avoiding warnings and conflicts.

function deepmagic($levels, $value)
{
    if(count($levels) > 0)
    {
        return array($levels[0] => deepmagic(array_slice($levels, 1),
            $value));
    }
    else
    {
        return $value;
    }
}

$a = deepmagic(Array('a', 'b', 'c', 'd'), 10);

var_dump($a);

Output:

array(1) {
  ["a"]=>
  array(1) {
    ["b"]=>
    array(1) {
      ["c"]=>
      array(1) {
        ["d"]=>
        int(10)
      }
    }
  }
}