Question

What is the easiest way to map array of objects to key-value array of objects, where key is some property of an object?

For example:

class Cartoon
{
  public $title;
  public function __construct($title)
  {
    $this->title = $title;
  }
}

$cartoons = array(new Cartoon('Tom and Jerry'), new Cartoon('Cheburashka'));

$mappedCartoons = array();

foreach ($cartoons as $cartoon)
{
  $mappedCartoons[$cartoon->title] = $cartoon;
}

print_r ($mappedCartoons);

PS. I wonder if iteration and the extra variable $mappedCartoons can be disposed of?

Answer 1

You could use array_reduce to achive your goal.

<?php

$cartoons = array_reduce($cartoons, function($result, $cartoon) {
  $result[$cartoon->title] = $cartoon;
  return $result;
}, array());

?>

the idea is not mine, found here: http://www.danielauener.com/howto-use-array_map-functionality-on-an-associative-array-changing-keys-and-values/