What's de deal with the && and the "and" operator ?

I just spent 10 minutes trying to understand this, and once I did I realized none of the answers here sufficiently hit the mark.

What is happening is this... Let's say we have the following code:

<?php

$var1 = true and false; // the value TRUE is assigned to $var1, the rest of the line is then ignored.

var_dump($var1); //var_dump simply dumps the value you had assigned to the variable above, which was TRUE.

$var2 = false and false // now the value FALSE is assigned to $var1, and the rest of the line is ignored.

// so when we var_dump...

var_dump($var2);

// it will now return false, because the rest of the code after the initial assignment of the first boolean to the variable is all ignored. Like it was never there.
?>

So just to really drive this home, we can use a couple extreme examples:

<?php

$foo = 1 and true and false and false or false and true or false and true;

// this looks outrageous, but var_dump will simply return the integer value 1. 
// You can visualize what is happening behind the scenes like this:

$foo = 1 //and true and false and false or false and true or false and true;

// or an even more outrageous example...

$bar = false and true and potato and broccoli and this_is_insane and what_is_going_on and aowidjaowubdaowiuhd;

// you can run the above code just fine, because the system assigns the value FALSE to $bar, and then ignores the rest of the line.
?>

Hopefully that helps. I realize this is an old thread, but I'm sure many people overthink this as I did and miss what is going on. They are trying to finish the logical evaluation - as I was doing - and that makes no sense.

Someone please correct me if I'm wrong, but this works in every scenario I can think of.

Have a look into operator precedence. Here is link to the manual.

Here is a copy of an user contribution note there:

Watch out for the difference of priority between 'and vs &&' or '|| vs or':

<?php
$bool = true && false;
var_dump($bool); // false, that's expected

$bool = true and false;
var_dump($bool); // true, ouch!
?>
Because 'and/or' have lower priority than '=' but '||/&&' have higher.

I also little bit confused about it. Can someone explain?

My question is, how common are values like this in a 'real job scenario'? I'm only reviewing php here, and so far(in my very limited experience) I've never come across an issue like this yet. Is this one of those 'just so we know' things?

The = sign that comes before the and/or has a higher precedence/importance so the and/or can't change the value of the statement.

Cory's answered filled the hole I was having. It didn't make sense how the variables were being evaluated. After reading his post it became more clear. But after reading Kat's I'm still a bit unsure about what qualifies something to be true or false.

For example why are both of these true?:

var_dump ((bool) 1); // bool(true) var_dump ((boo) -2); // bool(true)

It is all on operator precedence. && operator has a more precedence than AND operator. When && is used is the same as using parenthesis to establish order of operation. example:

3*(1+2)= since parenthesis are used addition will be perform first. it is the same as when we used && operator. I hope it helps. Take time to read php manual

regards

-f

$a = true && $b = true will evaluate to true.

$a = true && $b = false will evaluate to false

$a = false && $b = true will evaluate to false

$a = false && $b = false will evaluate to false.

When using an AND (&&) operator, it requires that ALL CONDITIONS evaluate to true before outputting an overall true or false. OR (||) only requires that part of the input evaluate to true in order to output true.