PHP 運算子

Arithmetic Operators

算術運算子拿來做數字的加、減、乘、除等等運算。

Operator	Name	Example	Result
+	Addiction	$x + $y	Sum of $x and $y
-	Substraction	$x - $y	Difference of $x and $y
*	Multiplication	$x * $y	Product of $x and $y
/	Division	$x / $y	Quotient of $x and $y
%	Moduls	$x % $y	Remainder of $x divided by $y
**	Exponentiation	$x ** $y	Result of raising $x to the $y’th power (Introduced in PHP 5.6)

Assignment Operators

賦值運算子用來將 value 寫入給 variable，左邊賦值給右邊。

Assignment	Same as	Description
x = y	x = y	The left operand gets set to the value of the expression on the right
x += y	x = x + y	Addition
x -= y	x = x - y	Subtraction
x *= y	x = x * y	Multiplication
x /= y	x = x / y	Division
x % y	x = x % y	Modulus

Comparison Operators

比對運算子拿來比對兩個variable or value。

Operator	Name	Example	Result
==	Equal	$x == $y	Returns true if $x is equal to $y
===	identical	$x === $y	Returns true if $x is equal to $y, and they are of the same type
!=	Not Equal	$x != $y	Returns true if $x is not equal to $y
<>	Not Equal	$x <> $y	Returns true if $x is not equal to $y
!==	Not identical	$x !== $y	Returns true if $x is not equal to $y, or they are not of the same type
>	Greater than	$x > $y	Returns true if $x is greater than $y
<	Less than	$x < $y	Returns true if $x is less than $y
>=	Greater than or equal to	$x >= $y	Returns true if $x is greater than or equal to $y
<=	Less than or equal to	$x <= $y	Returns true if $x is less than or equal to $y

Increment/Decrement Operators

遞增/遞減運算子用來增加或減少 variable 的 value。

Operator	Name	Description
++$x	Pre-increment	Increments $x by one, then returns $x
$x++	Post-increment	Returns $x, then increments $x by one
–$x	Pre-decrement	Decrements $x by one, then returns $x
$x–	Post-decrement	Returns $x, then decrements $x by one

Logic Operators

邏輯運算子用在 conditional statement(if else之類)

Operator	Name	Example	Result
and	And	$x and $y	True if both $x and $y are true
or	Or	$x or $y	True if either $x or $y is true
xor	Xor	$x xor $y	True if either $x or $y is true, but not both
&&	And	$x && $y	True if both $x and $y are true
ll	Or	$x ll $y	True if either $x or $y is true
!	Not	!$x	True if $x is not true

String Operators

PHP 有兩種運算子供 字串 使用。

Operator	Name	Example	Result
.	Concatenation	$txt1 . $txt2	Concatenation of $txt1 and $txt2
.=	Concatenation assignment	$txt1 .= $txt2	Appends $txt2 to $txt1

<?php
$txt1 = "Hello";
$txt2 = " world!";
echo $txt1 . $txt2; // 輸出結果為 Hello world!

$txt1 .= $txt2;
echo $txt1; // 輸出結果為 Hello world!
?>

Array Operators

Array 之間使用的運算子。

Operator	Name	Example	Result
+	Union	$x + $y	Union of $x and $y
==	Equality	$x == $y	Returns true if $x and $y have the same key/value pairs
===	Identity	$x === $y	Returns true if $x and $y have the same key/value pairs in the same order and of the same types
!=	Inequality	$x != $y	Returns true if $x is not equal to $y
<>	Inequality	$x <> $y	Returns true if $x is not equal to $y
!==	Non-identity	$x !== $y	Returns true if $x is not identical to $y

<?php
// Union
$x = array("a" => "red", "b" => "green");  
$y = array("c" => "blue", "d" => "yellow");  

print_r($x + $y); 
// Array ( [a] => red [b] => green [c] => blue [d] => yellow )
?>