Howto use array_map functionality on an associative array to change values *and* keys

November 9, 2012

$assoc_arr = array_reduce($arr, function ($result, $item) {
    $result[$item['text']] = $item['id'];
    return $result;
}, array());

The snippets story

I just ran into a problem with extracting data from an array, like the following one:

$arr = array(
   array(
      'id' => 22,
      'text' => 'Lorem'
   ),
   array(
      'id' => 25,
      'text' => 'ipsum'
   ),
);

From this array, I wanted to create another, associative array, with the following structure:

$assoc_arr = array(
   'Lorem' => 22,
   'ipsum' => 25
);

My first guess was the array_map function, but I had to realize that there is no way to manipulate the keys of the resulting array. After some googling, I discovered, that it is array_reduce you have to use for such a thing.

ps: I know, a simple foreach would have done the trick, but once on the path of functional programming, I didn’t want to leave it that fast

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