and
Example | Name | Result |
|---|---|---|
$a and $b | And | TRUE if both $a and $b are TRUE. |
$a or $b | Or | TRUE if either $a or $b is TRUE. |
$a xor $b | Xor | TRUE if either $a or $b is TRUE, but not both. |
! $a | Not | TRUE if $a is not TRUE. |
$a && $b | And | TRUE if both $a and $b are TRUE. |
$a || $b | Or | TRUE if either $a or $b is TRUE. |
The reason for the two different variations of "and" and "or" operators is that they operate at different precedences. (See Operator Precedence.)
Example #1 Logical operators illustrated
<?php
//?--------------------
//?foo()?will?never?get?called?as?those?operators?are?short-circuit
$a?=?(false?&&?foo());
$b?=?(true??||?foo());
$c?=?(false?and?foo());
$d?=?(true??or??foo());
//?--------------------
//?"||"?has?a?greater?precedence?than?"or"
//?The?result?of?the?expression?(false?||?true)?is?assigned?to?$e
//?Acts?like:?($e?=?(false?||?true))
$e?=?false?||?true;
//?The?constant?false?is?assigned?to?$f?before?the?"or"?operation?occurs
//?Acts?like:?(($f?=?false)?or?true)
$f?=?false?or?true;
var_dump($e,?$f);
//?--------------------
//?"&&"?has?a?greater?precedence?than?"and"
//?The?result?of?the?expression?(true?&&?false)?is?assigned?to?$g
//?Acts?like:?($g?=?(true?&&?false))
$g?=?true?&&?false;
//?The?constant?true?is?assigned?to?$h?before?the?"and"?operation?occurs
//?Acts?like:?(($h?=?true)?and?false)
$h?=?true?and?false;
var_dump($g,?$h);
?>The above example will output something similar to:
bool(true)
bool(false)
bool(false)
bool(true)← Incrementing/Decrementing Operators
String Operators →
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