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/* OP symbol (PHP) Action symbol
*
* According to the function of the operation symbol is divided into:
* One, arithmetic operator +-*/% + +--
* Two, string operators. Join operators
* Third, assignment operator = + = = *=/=%=. =
* Iv. comparison operators > < >= <= = = = = = = = <>!==
* Comparison operators---Conditional operators---relational operators
* Only one of the results after comparison: Boolean true False
* = = = does not only require the same content, but also requires the same type
*!== different content when comparing, also require different type
* Five, logical operators && OR and | | OR OR! or not
* Logical operators can only manipulate values of type bool and return a value of type bool
* Six, bit operators & | ^ ~ << >> >>>
* Seven, other operators? : ' @ + =:: & $
* ' to execute operating system kernel '
* @ To block out error messages
* It is recommended to use "()" to change the priority level of an expression
*
*% has two purposes: divide operation, control range, do not use decimals, and do not use negative numbers
*% will be the number of the operators on both sides to integer after the remainder.
*/
Use% symbol to judge leap year
$year = 2011;
if ($year%4==0 &&%year%100!=0) | | $year%400=0)
{
echo "Run Nian";
}
Else
{
echo "not run Nian";
}
+ +--Use of symbols
$a = 10;
$a + +; $a = $a +1; Use variables first, then increment by 1
+ + $a; $a = $a +1; Increment by 1 First, in the variable
$a--; $a = $a-1; Use the variable first, and then subtract 1 from it.
-$a; $a = $a-1; Subtract 1 First, then use the variable
echo $a; Result is 10
+ +--the difference between operations
$a = 10;
$b = $a ++;//b=10,a=11
$c =--$b;//c=9,b=9
$d = $c + + + + $c; d=20,c=11
$e = $d-----$d; d=18,e=2
Echo $d;
The string operator. The use
$name = "Tom";
$age = 27;
$height = 1.75;
echo "My name is: {$name} My age is: {$age} My height is: {$height} m
";
Echo ' My name is: '. $name. ' My age is: '. $age. ' My height is: '. $height ' m '. '
';
echo "\ $age =". $age; $age =27
echo "My name is: {$name} My age is: {$age} My height is: {$height} m
";//use of assignment operators
$a = 10;
$a +=10; $a = $a +10;
$a-=10; $a = $a-10;
$a *=10; //...
$a/=10; //...
$a%=10; $a = $a% 10;
$a. = "ABC";//$a = $a. " ABC ";
echo $a;
$str = '
'; $str. = '
'; $str. = '
';
$str. = ' | '; $str. = '
'; $str. = '
';
echo $str;//Output a table
Comparison operators
Var_dump (15>6);//returns BOOL (TRUE)
$a = 15;
if (15== $a)
{
echo "A=15";
}
Else
{
echo "A!=15";
}
Use of logical operators
Var_dump (True && true);//true
Var_dump (True && false);//false
Var_dump (True | | false);//true
Var_dump (!true);//false
Var_dump (!false);//true
Determine User name password
$username = "admin";
$password = "123456";
$email = "290080604@qq.com";
if ($username = = "Admin" && $password = "123456")
{
echo "User name password is correct";
}
if ($username = = "" | | $password = = "" | | $email = = "")
{
echo "One cannot be empty";
}
Bitwise operators
$a = 20; 00010100
$b = 30; 00011110
/*
* 20 00010100
* 00011110 &
*-----------------------------------
* 00010100
*
*/
$c = $a & $b;
Echo $c;
/* Supplemental,& | It can also be used as a logical operation
* && | | Short-circuit problem:
* && at the time of operation, if the previous number is false, then whether the following is true, the entire expression is false, so do not go to the subsequent operand;
* || In the case of an operation, if the preceding number is true, then whether the subsequent number is false and the entire expression is true, the subsequent operand is not executed;
* However,& or | Both sides will be executed when the operation is performed.
*/
$a = 10;
if ($a >5 | | $a ++<100) {}
echo $a;//Output 10
$b = 10;
if ($b >5 | $b ++<100) {}
echo $b;//Output 11
/*
Bit concept: A bit is made up of 8 binary numbers (Example 00000000),
A byte consists of 8 bits, then there are 32 binary numbers.
Original code: Highest bit with 0 for positive, 1 for negative
+7 00000111
-7 10000111
Anti-code: If a number is positive, then its inverse code and the same as the original code;
If a number is negative, then the sign bit is 1, the rest of you are the original code to take the reverse;
+7 00000111
-7 11111000
+0 00000000
-0 11111111
Complement: If a number is positive, then its complement and inverse code are the same as the original code
A number if negative, then its complement = anti-code +1, remove the highest bit overflow bit
-7 Original Code 10000111 anti-code 11111000
+1
Complement 11111001
The complement of a negative number is known, and it is converted to decimal.
1. First, you take the counter
2. Convert it to a decimal number
3. Add minus, minus 1.
Example: Complement 11111010
Take the reverse 00000101
4+1=5
-5-1=-6
Bitwise operators:
& Bitwise vs. bitwise OR ^ bitwise XOR or ~ bitwise inverse
Example: Bitwise AND 01101101
&00110111
00100101
Conclusion: Only 1 1 is 1.
Bitwise OR 01101101
|00110111
01111111
Conclusion: only 0 0 is 0.
Bitwise XOR or 01101101
^00110111
01011010
Conclusion: only 1 0 or 0 1 o'clock is 1. (can also be understood as being in a different state of 1 (true))
Bitwise REVERSE ~00110111
11001000
Conclusion: Change 0 to 0
Shift operators:
Move left:<< sign right:>> unsigned right shift:>>>
Example: Number x x<<2 x>>2 x>>>2
17 00010001 01000100) 00000100 00000100
-17 11101111 10111100 11111011 00111011
Conclusion: Positive movement is 0, negative left 0, with symbol right shift 1, without symbol complement 0
*/
The use of other operators
$a = 10;
$b = $a >5? $a: 5;//ternary operator If $b= is established $a otherwise $b=5
Echo $b;
Use "to execute operating system shell commands
$str = ' Ipconfig/all ';
Echo '
Echo '
';
?>
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