Question

How can I modify the next element in a foreach() loop, during the loop? I think it has something to do with talking to the variable by reference but I’m not sure how. i.e.:

$arr = array( array('color' => 'red',    'type' => 'apple'),
              array('color' => 'yellow', 'type' => 'banana'),
              array('color' => 'purple', 'type' => 'grape')
            );

foreach($arr as $k => $v) {
   echo "<br> The ".$v['type'].' fruit is '.$v['color'];

   // change the color of the next fruit?
   if($v['type'] == 'apple') { $arr[$k+1]['color'] = 'green'; }
}

I’d like this to tell me the banana is green, but it stubbornly sticks to the banana being yellow…

(UPDATE: fixed a stupid logic error in my original question. The answer marked below is correct.)

Answer 1

foreach loops through an array by taking a copy of the array and not by reference. You need to loop through the array by reference using the ampersand & on the array value.

foreach($arr as $k => &$v) {
   echo "<br> The ".$v['type'].' fruit is '.$v['color'];

   // change the color of the next fruit?
   if($v['type'] == 'banana') { $arr[$k+1]['color'] = 'green'; }
}