PHP Mobile Internet Development Notes (3)--operator

First, the PHP operator

PHP has a rich set of operators, most of which come directly from the C language. The operators can be divided into arithmetic operators, string operators, assignment operators, bitwise operators, conditional operators, and logical operators, according to different functions. When the various operators are in the same expression, their operations are given a certain degree of precedence.

(1) Arithmetic operation

+    -   *   /  %  ++ --

(2) string operator

There is only one string operator. (point) is the end of English. It can concatenate strings, form a new string, or concatenate a string with a number, when the type is automatically converted.

	$a = "Dawanganban";  
$b = "123";  
echo $a. $b;   Output Result: dawanganban123  

(3) Assignment operator

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



$a = "Dawanganban";  
$a. =1;  
$a. =2;  
$a. =3;  
echo $a. $b;   Output Result: dawanganban123  

(4) Bitwise operator & ~ ^ << >>

(5) Comparison operators

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

<>: For not equal to and! = Same

= =: identity, value equal and type consistent

！ = =: Non-identity, unequal value or inconsistent type

1. 	echo 5 = "5"; True  PHP is a weakly typed language (similar to a variable in JS)  
   echo 5 = = "5";  False is  exactly equal to  

(6) Logical operation

and (logical vs.) or (logical OR) XOR (logical XOR) && (Logic and) (logic or)! (Logical non)

	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