PHP operator classification description and summary of some special operators

1. Classification of operators

1. Classification by operand

1.!true // Unary operator
2.$a+$b // Binary operation Symbol
3.true ? 1:0 //Ternary operator

2, classified by operation function

(1)Arithmetic operator
1.+, -, x, /, % (remainder)

(2) String operator
1.. // For example: $a = 'abc'.'efg';

(3)Assignment operator

1.= // Simple assignment
2.+=,-=, X=, /=, %=, .= // Compound assignment
3.++($a++, ++$a), --($a--,--$a) // Increasing and decreasing
4.&($a = 1;$b = &a) // Reference assignment

(4)Comparison operator

1.==, = ==(constantly equal to), !=, !===, <>(not equal to), <, >, <=, >=

（5）Logical operators
1.// The precedence inside the brackets is higher than the precedence outside the brackets
2.&&(and), ||(or), !(not), xor(exclusive or ),

(6) bit operators
1.& (bitwise AND), | (bitwise OR), ~ (bitwise NOT), ^ (bitwise XOR) , <<(left shift), >>(right shift)

2. Arithmetic operator

% takes remainder, common usage: 1) Integer division operation 2) Control taking Value range

Example: Determine whether it is a leap year (one leap year every four years, no leap years, and another leap year after four hundred years)

// %会把两边的数转成整型后在整除
// %两边不能用小数或负数
if ((($year%4 == 0) && ($year%100 != 0)) || $year%400 == 0)
echo "闰年";
else
echo "平年";

3. Assignment operator

//先自身加10，然后赋值给自己，等价于 $a=$a+10
$a += 10;
  
//前置递增递减，先递增递减再赋值
++$a
 
//先赋值，再递增递减
$a++
//实例
$a = 10;
$b = $a++
$c = --$b
结果：a=11 b=9 c=9

4 , Logical operator

xor exclusive or: the same is false (two true or two false = false), different is true (one true and one false = false)
Tips: Pay attention to the difference with or, or Two true = true
Logical operators short-circuit
1, && //If one is false, then no operation will be performed later, it must be false
2, || //If one is true, then no operation will be performed later, Must be true

fopen ("test.php","r") or die("failure");

Tips: There is no short-circuit feature for operator & |

5. Bit operators

Bit operations: Convert integers to 32-bit binary, and convert strings to ANSCA codes for processing

6. Special operators

Annotations Symbol:
                                                                                                                                             Dynamically processed and then output, generally used to process $variables.
Boolean variables:
                                                                                                                                                                                                                      ==================================================================================================================== String (numbers\Chinese characters\etc.)
integer integer (1, 2, 3, 4, 5, 0, -1, -2, etc.)
double floating point number (decimal point)
array Array
object object
The methods that can be used are gettype($mix) and settype($mix,$typename);

Common symbol escape:

                                                                                                                                             Table
Operation symbols:
                                                                                                                                                           Subtraction operations Decrement by 1. Concatenate two strings.
Assignment operation:
= = Change the value on the right Substituting the left side
                                                                                           ‐       ‐ ‐ ‐                                                 using using using using using using using using using   using       using using using using using using using using using                  doing out into out out out out out out of''' being'' ‐ in   ‐ ‐ ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ ‐- -   -       -
. << ; Shift 1 bit to the left
                                                                                                                                       =                                                                                                                                                                            Variable symbol                                                                                                                                                                                                                                                              
(Add before function)
                                                                                                                                                                                            With Withdrawal                                                =>

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