How to update code that uses the deprecated each() function

Question

With PHP 7.2, the each function has been deprecated. The documentation mentions:

Warning As of PHP 7.2.0, this function has been deprecated. Reliance on this function is strongly discouraged.

How do I update my code to avoid using it? Here are some examples:

1. $ar = $o->me;
   reset($ar);
   list($typ, $val) = each($ar);

2. $out = array('me' => array(), 'mytype' => 2, '_php_class' => null);
   $expected = each($out);

3. for(reset($broken);$kv = each($broken);) {...}

4. list(, $this->result) = each($this->cache_data);

5. // iterating to the end of an array or a limit > the length of the array
   $i = 0;
   reset($array);
   while( (list($id, $item) = each($array)) || $i < 30 ) {
       // code
       $i;
   }

When I execute the code on PHP 7.2, I receive the following error:

Deprecated: The each() function has been deprecated. This message will be ignored on further calls

Answer 1

2019 Instant Upgradeeach()

There are actually many situations where each() can be replaced, which is why there are so many different upvoted answers in this question.

-while (list($key, $callback) = each($callbacks)) {
+foreach ($callbacks as $key => $callback) {
     // ...
 }

besides:

-while (list($key) = each($callbacks)) {
+foreach (array_keys($callbacks) as $key) {
     // ...
 }

You can replace them one by one manually. But isn't there a better way?

I help with migration projects and have over 150 cases like this. I'm lazy, so I made a tool called Rector that can convert the code into the above way (there are more cases, but I don't want to spam the answer) .

It is part of the PHP_72 collection.

4 Steps to Upgrade Your Code

1. Installation

composer require rector/rector --dev

2. Create rector.phpConfiguration file

vendor/bin/rector init

3. Add PHP_72Collection

<?php

use Rector\Core\Configuration\Option;
use Rector\Set\ValueObject\SetList;
use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;

return static function (ContainerConfigurator $containerConfigurator): void {
    $parameters->set(Option::SETS, [
        Setlist::PHP_72,
    ]);
};

4. Run it on your code

vendor/bin/rector process src --set php72

Hope it helps with your migration.

If there are any errors or exceptions, that's what Rector missed. Create an issue so we can fix it and make it work for all possible cases.

Answer 2

1. For your first two example cases, you can use key() and current() to assign the values ​​you need.

   $ar = $o->me;   // 重置不是必需的，因为你刚刚创建了数组
   $typ = key($ar);
   $val = current($ar);

2. $out = array('me' => array(), 'mytype' => 2, '_php_class' => null);
   $expected = [key($out), current($out)];

   In these cases you can use next() to advance the cursor afterwards, but this may not be necessary if the rest of your code does not rely on it.

3. For the third case, I suggest you just use a foreach() loop and allocate $kv inside the loop.

   foreach ($broken as $k => $v) {
        $kv = [$k, $v];
   }

4. For the fourth case, the key seems to be ignored in list() so you can assign the current value.

   $this->result = current($this->cache_data);

   Like the first two cases, depending on how the rest of your code interacts with $this->cache_data, you may need to advance the cursor using next().

5. The fifth case can be replaced by for() loop.

   reset($array);
   for ($i = 0; $i < 30; $i++) {
       $id = key($array);
       $item = current($array);
       // 代码
       next($array);
   }