Question

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.

Answer 1

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);
?>

Answer 2

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.

Answer 3

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)
      }
    }
  }
}

友情链接