How to replace values in a nested array with array_walk?

Question

This is my array,

$item = array(
    "id" => "2",
    "title" => "parent 2",
    "children" => array (
           "id" => "4",
           "title" => "children 1"
        )
);

//replacement array:
$replace = [
  '2' => 'foo',
  '4' => 'bar',
  '7' => 'baz'
];

My working function,

function myfunction(&$value,$key,$replace)
{   

    if(isset($replace[$key]))
    {
       $value = $replace[$key];
    }

    if(is_array($key))
    {
        array_walk($value,"myfunction",$replace);
    }
}

array_walk($item,"myfunction",$replace);

print_r($item);

result,

Array
(
    [id] => 2
    [title] => parent 2
    [children] => Array
        (
            [id] => 4
            [title] => children 1
        )

)

The result I'm after,

Array
(
    [id] => 2
    [title] => foo
    [children] => Array
        (
            [id] => 4
            [title] => bar
        )

)

Khalid · Accepted Answer · 2014-07-20 15:58:20Z

2

This recursive function may help you

function replace($item,$replace)
{
    foreach ($replace as $key => $value) 
    {
        if($item["id"]==$key)
            $item["title"] = $value;
        if(isset($item['children']))
            $item['children'] = replace($item['children'],$replace);
    }
    return $item;
}

it doesn't modify $item, it returns it modified, so you need to call it like this

$item = replace($item,$replace);

In order to make your function modify the argument $item, just pass it by reference like this :

function replace(&$item,$replace)
{
    foreach ($replace as $key => $value) 
    {
        if($item["id"]==$key)
            $item["title"] = $value;
        if(isset($item['children']))
            replace($item['children'],$replace);
    }
}

In this case you just need to call the function like this :

replace($item,$replace);
print_r($item);

answered Jul 20, 2014 at 15:58

Khalid

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2 Comments

Run Over a year ago

Thanks! So I don't need array_walk in this case then?

Drew Baker Over a year ago

What should $item and $replace be in your final function?

Zahra Badri · Accepted Answer · 2021-05-18 05:28:28Z

0

Try this function :

    function replaceKey($subject, $newKey, $oldKey) {

    if (!is_array($subject)) return $subject;

    $newArray = array(); // empty array to hold copy of subject
    foreach ($subject as $key => $value) {

        // replace the key with the new key only if it is the old key
        $key = ($key === $oldKey) ? $newKey : $key;

        // add the value with the recursive call
        $newArray[$key] = $this->replaceKey($value, $newKey, $oldKey);
    }
    return $newArray;
}

answered May 18, 2021 at 5:28

Zahra Badri

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