PHP Mobile Internet Development Notes (3) - Operator_PHP Tutorial

1. PHP operators

There is a rich set of operators in PHP, most of which come directly from the C language. According to different functions, operators can be divided into: arithmetic operators, string operators, assignment operators, bit operators, conditional operators, and logical operators. When various operators are in the same expression, their operations have a certain priority.

(1) Arithmetic operations

+ - * / % ++ --

(2) String operator

There is only one string operator. (dot) is the English period. It can concatenate strings to form a new string, or it can concatenate strings with numbers, and the types will be automatically converted.

	$a="dawanganban";  
$b="123";  
echo $a.$b;   //输出结果：dawanganban123  

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(3) Assignment operator

	= += -= *= /= %= .=



$a="dawanganban";  
$a.=1;  
$a.=2;  
$a.=3;  
echo $a.$b;   //输出结果：dawanganban123  

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(4) Bit operators ​ & | ~ ^ << >>

(5) Comparison operators

> < >= <= == != <> === !==

<>: is not equal to sum! =Same

===: Identity, the values ​​are equal and the types are consistent

! ==: non-identity, values ​​are not equal or types are inconsistent

1. 	echo 5 == "5"; //true  PHP是弱类型语言（js中的变量类似）  
   echo 5 === "5";  //false  完全等于  

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(6) Logical operations

AND (logical AND) OR (logical OR) XOR (logical exclusive OR) && (logical AND) || (logical OR) ! (logical NOT)

	var_dump(5 && "");   //false  
var_dump(5 && "2"); //true  
var_dump(5 || ""); //true  
var_dump(0 xor 1); //true  
var_dump(0 xor 0); //false  
var_dump(1 xor 1); //false  

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