What is => in codeigniter

just a simple question

In this example, what does => do? and how to read it?

is it read by "is to" or "is equal"

$array = array(
    'color' => 'red',
    'shape' => 'round',
    'radius' => '10',
    'diameter' => '20'
);

Answer

Well, its not is to or is equal but the sign => is an assignment operator to assign values in array's indexes.

For example:

$x[0] = 10;
$x[1] = 20;
$x[2] = 30;
$x[3] = 40;

Or

$x = (0 => 10,
      1 => 20,
      2 => 30,
      3 => 40,
    );