Strange behavior with PHP 'and' operator

Question

I am having trouble understanding the behavior of the 'and' PHP operator.

Here is the code:

$condition1 = true;
$var2 = "var2";
$var3 = "var3";

$condition2 = $condition1 and $var2 == $var3;

if($condition2)
    echo '$condition1 and $var2 == $var3';

Output: $condition1 and $var2 == $var3

Now it is obvious that since $var2 != $var3, $condition2 should be false. Hence the echo statement should not be executed but it happens the other way. Can any one tell me what's wrong with this code?

Answer 1

Use && instead of and.

and has lesser precedence than &&. The statement

$condition2 = $condition1 and $var2 == $var3;

is executed in two steps from left to right.

1: $condition2 = $condition1 is executed. i.e. $condition2 is true now.

2: $var2 == $var3; is executed which performs the evaluation but does not assign any value to any variable.

Answer 2

I think this is an operator precedence issue. Try this instead:

$condition2 = ($condition1 and $var2 == $var3);

I think the issue is that your current code gets interpreted like this:

($condition2 = $condition1) and ($var2 == $var3)