PHP operator Classification description and some special operator summaries

I. Classification of Operators

1, by Operation number classification

1.!true//Unary operators
2. $a + $b//two-dollar operator
3.true? 1:0//ternary operator

2, according to the function classification

(1) Arithmetic operators
1.+ 、-、 x,/,% (take more)

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

(3) Assignment operator

1.=//Simple Assignment
2.+=,-=, x=,/=,%=,. =//Compound assignment
3.++ ($a + +, + + $a),--($a--、--$a)//increment decrement
4.& ($a = 1; $b = &a)//reference assignment

(4) Comparison operators

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

(5) Logical operators
1.//in parentheses with higher precedence than outside parentheses
2.&& (and), | | (OR),! (not), XOR (heterogeneous),

(6) Bitwise operator
1.& (Bitwise AND), | (bitwise OR), ~ (bitwise non), ^ (bitwise XOR), << (left shift), >> (right Shift)

Second, arithmetic operators

% remainder, common usage: 1) integer Division operation 2) control range of values

Example: Judging whether it is a leap year (four years a leap, a century does not leap, 400 years again leap)

% will turn the number of the two sides into integer after the division//% can not be used with decimals or negative if ((($year%4 = = 0) && ($year%100! = 0)) | | $year%400 = 0) echo "Leap year"; Elseecho "common year" ;

Three, assignment operators

First add 10, and then assign to yourself, equivalent to $a = $a +10$a + = ten;  Increment decrement, increment decrement and assign value + + $a//first assignment, then increment decrement $a++//instance $ A = ten, $b = $a + + $c =--$b result: a=11 b=9 c=9

Four, logical operators

XOR: Same as False (two true or two false = False), different for true (one true false = False)
Tips: Note the difference from or two true = True
Logical operator Short Circuit
1, &&//A false, then do not operate, must be false
2, | | One is true, then there is no operation behind it, it must be true.

fopen ("test.php", "R") or Die ("failure");

Tips: For Operators & | No short circuit characteristics

Five, bitwise operators

Bit operation: Convert integer to 32-bit binary, string to Ansca code to handle

VI. Special Operators

Annotation symbols:
Single-line annotations
Multi-line annotations
Use of quotation marks
' Single quotation marks, simple strings, are taken directly by any processing;
"" Double quotes, PHP dynamic processing then output, typically used to process the $ variable.
Boolean variable:
One is true, that is true;
The other is false or false.
Common variables:
string strings (numeric \ Kanji \ etc)
Integer integers (1, 2, 3, 4, 5, 0, 1, 2, and so on)
Double floating point number (decimal point)
Array arrays
Object objects
Available methods are GetType ($mix) and Settype ($mix, $typename);

Common symbol escapes:

\ "Double quotation marks
\ \ Backslash
\ nthe line break
\ r back to the beginning
\ t Horizontal Tabulation
Operation Symbols:
+ addition operations-subtraction operations
* Multiplication Operation/division operation
% take remainder + + 1
--Self minus 1. Connect two strings
Assignment operation:
= Put the value on the right side into the left
+ = Add the right value to the left
-= reduce the value on the right to the left
*= multiply the left value by the right.
/= divide the left value to the right
. = Add the right string to the left
Bit operations:
& Bitwise AND
| Bitwise OR
^ Bitwise XOR (XOR)
<< Move left 1-bit
>> Move right 1-bit
~ Fetch the number of complements
Logical operation:
< less than > greater than
<= less than or equal to >= greater than or equal
! = is not equal to &&
|| Or! Non -
Other operational symbols
$ variable Symbol
& Variable Alias
@ Do not display error message (added before function)
The method or property of the object
= = element value of array
?: Ternary operator