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: $a = 'abc'.'efg';
1.= // Simple assignment
2.+=,-=, X=, /=, %=, .= // Compound assignment
3.++($a++, ++$a), --($a--,--$a) // Increasing and decreasing
4.&($a = 1;$b = &a) // Reference assignment
1.==, = ==(constantly equal to), !=, !===, <>(not equal to), <, >, <=, >=
(5)Logical operators
1.// The precedence inside the brackets is higher than the precedence outside the brackets
2.&&(and), ||(or), !(not), xor(exclusive or ),
(6) bit operators
1.& (bitwise AND), | (bitwise OR), ~ (bitwise NOT), ^ (bitwise XOR) , <<(left shift), >>(right shift)
2. Arithmetic operator
% takes remainder, common usage: 1) Integer division operation 2) Control taking Value range
Example: Determine whether it is a leap year (one leap year every four years, no leap years, and another leap year after four hundred years)
// %会把两边的数转成整型后在整除 // %两边不能用小数或负数 if ((($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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