PHP/Operator/Operator Precedence

Operator Precedence

 
Associativity          Operators
left                   ,
left                   or
left                   xor
left                   and
right                  print
left                   = += -= *= /= .=%=&= |= ^= ~= «= »=
left                   ? :
left                   ||
left                   &&
left                   |
left                   ^
left                   &
non-associative        == != ===
non-associative        < <= > >=
left                   << >>
left                   + - .
left                   * /%
right                  ! ~ ++ � (int) (double) (string) (array) (object) @
right                  [
non-associative        new

Operator Precedence summary table

Operator                Class                 Associativity
new                     Unary                 n/a
[                       Unary                 Right
!                       Unary                 ! and ~ are right associative;
~                                             ++ and-- operators are right or left associative
++ 
-- 
(int) 
(double) 
(string) 
(array) 
(object)
 @
-------------------------------------------------------------------------------------  
* / %                  Binary                 Left
+ - .                  Binary                 Left
<< >>                  Binary                 Left
< <= > >=              Binary                 n/a
== != === !==          Binary                 n/a
&                      Binary                 Left
^                      Binary                 Left
|                      Binary                 Left
&&                     Binary                 Left
||                     Binary                 Left
?:                     Ternary                Left
=                      Binary                 Left
+= 
-= 
*= 
/= 
.= 
%= 
&= 
|= 
^= 
~= 
<<= 
>>=
  
print                 Unary                    Right
and                   Binary                   Left
xor                   Binary                   Left
or                    Binary                   Left
,                     n/a                      Left

Operators, precedence, and their associativity

 
Operators                                                        Associativity
 
,             Left                                               "$x, $y, $z" is "($x, $y), $z"
 
or            Left                                               "$x OR $y OR $z" is "($x OR $y) OR $z"
 
xor           left                                               "x XOR y XOR z" is "($x XOR $y) XOR $z"
 
and           Left                                               "x AND y AND z" is "(x AND y) AND z"
 
= += -= * = /= .= %= &= |= ^= <<= gt;>=           Right          "$x /= $y /= $z" is "$x /= ($y /= $z)"
 
? :           Left  
||            Left                                               "$x || $y || $z" is "($x || $y) || $z"
 
&&            Left                                               "$x && $y && $z" is "($x && $y) && $z"
 
|             Left                                               "$x | $y | $z" is "($x | $y) | $z"
 
^             Left                                               "$x ^ $y ^ $z" is "($x ^ $y) ^ $z"
 
&             Left                                               "$x & $y & $z" is "($x & $y) & $z"
 
== != === !==                Non-associative
   
< < = > >=                    Non-associative
   
<< >>          Left                                               "$x >> $y >> $z" is "($x >> $y) >> $z"
 
+ - .          Left                                               "$x - $y - $z" is "($x - $y) - $z"
 
* / %          Left                                               "$x / $y / $z" is "($x / $y) / $z"
 
! ~ ++ -- (int) (float) (string)(array) (object) @     Right
   
[              Right  
new            Non-associative

Using the ? Operator

 
The ?, or ternary, operator returns a value derived from one of two expressions separated by a colon. 
(expression) ?returned_if_expression_is_true:returned_if_expression_is_false;
If the test expression evaluates to true, the result of the second expression is returned; 
otherwise, the value of the third expression is returned. 

<html>
<body>
<div>
<?php
    $satisfied = "no";
    
    $pleased = "very";
    $sorry = "sorry";
    
    $text = ( $satisfied=="very" )?$pleased:$sorry;
    print "$text";
?>
</div>
</body>
</html>

Using the ? operator to create a message

 
<?php
$logged_in = TRUE;
$user = "Admin";
$banner = ($logged_in==TRUE)?"Welcome back, $user!":"Please login.";
echo "$banner";
?>