如何更新使用已弃用 each() 函数的代码?

With PHP 7.2, each is deprecated. The documentation says:

Warning This function has been DEPRECATED as of PHP 7.2.0. Relying on this function is highly discouraged.

How can 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 is deprecated. This message will be suppressed on further calls

解决方案

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

   $ar = $o->me;   // reset isn't necessary, since you just created the array
   $typ = key($ar);
   $val = current($ar);
   

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

   In those cases, you can use next() to advance the cursor afterward, but it may not be necessary if the rest of your code doesn't depend on that.

3. For the third case, I'd suggest just using a foreach() loop instead and assigning $kv inside the loop.

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

4. For the fourth case, it looks like the key is disregarded in list(), so you can assign the current value.

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

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

5. Fifth can be replaced with a for() loop.

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