PHP managing multidimensional array values

Question

I have a result set as an array from a database that looks like this:

array (
    0 => array (
        "a" => "something"
        "b" => "something"
        "c" => "something"
    )
    1 => array (
        "a" => "something"
        "b" => "something"
        "c" => "something"
    )
    2 => array (
        "a" => "something"
        "b" => "something"
        "c" => "something"
    )
)

How to apply a function to replace array values ​​only with an array key using b? Normally, I would just rebuild the new array with the foreach loop and apply the function if the array key is b, but I'm not sure if this is the best way. I tried to take a look at the many functions of the array, and it seemed that array_walk_recursive is what I can use, but I was not lucky that it did what I want. If I will not describe it well enough, basically I want to be able to do as the following code does:

$arr = array();
foreach ($result as $key => $value)
{
    foreach ($value as $key2 => $value2)
    {
        $arr[$key][$key2] = ($key2 == 'b' ? $this->_my_method($value2) : $value2);
    }    
}

Should I stick with this, or is there a better way?

Answer 1

array_walk_recursive:

PHP >= 5.3.0 ( ):

array_walk_recursive($result, function (&$item, $key) {
    if ($key == 'b') {
        $item = 'the key is b!';
    }
});

- :

function _my_method(&$item, $key) {
    if ($key == 'b') {
        $item = 'the key is b!';
    }
}
array_walk_recursive($result, '_my_method');

Answer 2

, , .

function replace_b (&$arr)
{
    foreach ($arr as $k => $v)
    {
        if ($k == 'b')
        {
            /* Do something */
        }
        if (is_array($v)
        {
            replace_b($arr[$k]);
        }
    }
}

, b. , .

Answer 3

use array_walk_recursive described here

$replacer = function($x) {return "I used to be called $x";}; //put what you need here
$replaceB = function(&$v, $k) use ($replacer) {if ($k === 'b') $v = $replacer($v);};

array_walk_recursive($arr, $replaceB);

Function replacermay be redundant. You can replace it with a literal or whatever you like.