Basic Assignment

$a = "some string";

results in $a having the value some string.

The result of an assignment expression is the value being assigned. Note that a single equal sign = is NOT for comparison!

$a = 3;
$b = ($a = 5);

does the following:

1. Line 1 assigns 3 to $a.
2. Line 2 assigns 5 to $a. This expression yields value 5 as well.
3. Line 2 then assigns the result of the expression in parentheses (5) to $b.

Thus: both $a and $b now have value 5.