PHP Syntax 1

The reference methods of static methods and static properties in classes
such as
class Test{
     public static $test = 1;
    public static function test(){
    }
}

can directly use Test::$test to obtain the value of the $test property without instantiating the object
statically The same is true for method calls Test::test(); directly call the static method test

 

=>
keys generally used for arrays => values
​​->
objects generally used for objects -> object properties and objects -> object methods

 

=== : compare the size, and also compare whether the types are the same
== : only compare the size

 

Operator Description
<<< Pipe, introduced from c++. The content enclosed by the following tags is treated as a string, and the variables in it will be expanded
<< left shift, bit operator
>> right shift, bit operator
== equal, logical operator. Automatic conversion of the data types involved in the operand
=== Identical equals, logical operator. Do not convert data type
>>> no such operator

 

PHP arithmetic operators

operator name example result

+	addition	$x + $y	sum $x and $y
-	subtraction	$x - $y	difference between $x and $y
*	multiplication	$x * $y	Product of $x and $y
/	division	$x / $y	Quotient of $x and $y
%	modulus	$x % $y	Remainder of $x divided by $y

The following examples show different results using different arithmetic operators:

example

<?php
$x=10;
$y=6;
echo ($x + $y); // prints 16 
echo ($x - $y); // prints 4 
echo ($x * $y); // prints 60 
echo ($x / $y); // output 1.6666666666667 
echo ($x % $y); // output 4
?>

running instance

 

PHP assignment operator

The PHP assignment operator is used to write values ​​to variables.

The basic assignment operator in PHP is "=". This means that the right-hand assignment expression sets the value of the left-hand operand.

Assignment is equivalent to description

x = y	x = y	The expression on the right sets the value for the operand on the left.
x += y	x = x + y	add
x -= y	x = x - y	reduce
x *= y	x = x * y	take
x /= y	x = x / y	remove
x %= y	x = x % y	modulus

The following examples show different results using different assignment operators:

example

<?php
$x=10;
echo $x; // output 10

$y=20;
$y += 100;
echo $y; // output 120

$ z = 50;
$ z - = 25;
echo $z; // output 25

$i=5;
$i *= 6;
echo $i; // output 30

$j=10;
$j /= 5;
echo $j; // output 2

$k=15;
$k %= 4;
echo $k; // output 3
?>

running instance

PHP string operators

operator name example result

.	tandem	$txt1 = "Hello" $txt2 = $txt1 . " world!"	$txt2 now contains "Hello world!"
.=	concatenation assignment	$txt1 = "Hello" $txt1 .= " world!"	$txt1 now contains "Hello world!"

The following example shows the result of using string operators:

example

<?php
$a = "Hello";
$b = $a . " world!";
echo $b; // print Hello world!

$x="Hello";
$x .= " world!";
echo $x; // output Hello world!
?>

running instance

PHP increment/decrement operators

operator name description

++$x	pre-increment	Increment $x by one, then return $x
$x++	post increment	Returns $x, then increments $x by one
--$x	pre-decrement	Decrement $x by one, then return $x
$x--	post decrement	Return $x, then decrement $x by one

The following examples show different results using different increment/decrement operators:

example

<?php
$x=10;
echo ++$x; // output 11

$y=10;
echo $y++; // output 10

$ z = 5;
echo --$z; // output 4

$i=5;
echo $i--; // output 5
?>

running instance

PHP comparison operators

PHP comparison operators are used to compare two values ​​(numbers or strings):

operator name example result

==	equal	$x == $y	Returns true if $x is equal to $y.
===	Congruent (exactly the same)	$x === $y	Returns true if $x is equal to $y and they are of the same type.
!=	not equal to	$x != $y	Returns true if $x is not equal to $y.
<>	not equal to	$x <> $y	Returns true if $x is not equal to $y.
!==	not equal (completely different)	$x !== $y	Returns true if $x is not equal to $y and they are not of the same type.
>	more than the	$x > $y	Returns true if $x is greater than $y.
<	more than the	$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.

The following examples show different results using some comparison operators:

example

<?php
$x=100;
$y="100";

var_dump($x == $y);
echo "<br>";
var_dump($x === $y);
echo "<br>";
var_dump($x != $y);
echo "<br>";
var_dump($x !== $y);
echo "<br>";

$a=50;
$b=90;

var_dump($a > $b);
echo "<br>";
var_dump($a < $b);
?>

running instance

PHP logical operators

operator name example result

and	and	$x and $y	Returns true if both $x and $y are true.
or	or	$x or $y	Returns true if at least one of $x and $y is true.
xor	XOR	$ x xor $ y	Returns true if one and only one of $x and $y is true.
&&	and	$x && $y	Returns true if both $x and $y are true.
||	or	$x || $y	Returns true if at least one of $x and $y is true.
!	No	!$x	Returns true if $x is not true.

PHP array operators

PHP array operators are used to compare arrays:

operator name example result

+	joint	$x + $y	$x 和 $y 的联合（但不覆盖重复的键）
==	相等	$x == $y	如果 $x 和 $y 拥有相同的键/值对，则返回 true。
===	全等	$x === $y	如果 $x 和 $y 拥有相同的键/值对，且顺序相同类型相同，则返回 true。
!=	不相等	$x != $y	如果 $x 不等于 $y，则返回 true。
<>	不相等	$x <> $y	如果 $x 不等于 $y，则返回 true。
!==	不全等	$x !== $y	如果 $x 与 $y 完全不同，则返回 true。

下例展示了使用不同数组运算符的不同结果：

实例

<?php
$x = array("a" => "red", "b" => "green"); 
$y = array("c" => "blue", "d" => "yellow"); 
$z = $x + $y; // $x 与 $y 的联合
var_dump($z);
var_dump($x == $y);
var_dump($x === $y);
var_dump($x != $y);
var_dump($x <> $y);
var_dump($x !== $y);
?>