Incrementing numbers doesn't give an error

Question

How come this code below echo's 2 and does not give an error, does it just ignore +1+2+3+4 ?

I've searched but couldn't find an answer.

<?php
$i = 1;
$i+++1+2+3+4;
echo $i;

Answer 1

That line:

$i+++1+2+3+4;

Says:

• Increment $i
• Add the value of $i pre increment to +1+2+3+4, but don't store the result anywhere.

Hence $i == 2.

If you wouldn't want it to be ignored, you should store the result:

$i = $i+++1+2+3+4;