What is += used for?

Question

I think this is a dumb question but I could not find it on php. Why is a + with the = in the following code:

function calculateRanking()
{
    $created = $th         


        

Answer 1

Let's replace a few things to make it a bit easier to understand.

The += is just the same as below:

$time = $diff['days'] * 24;
$time = $time + $diff['hours'];
$time = $time + ($diff['minutes'] / 60);
$time = $time + (($diff['seconds'] / 60)/60);