Arithmetic operators
Operator name Result
$a + $b addition $a and $b and
$a-the difference between $b subtraction $a and $b
$a * $b multiplication $a and the product of $b
$a/$b division $a divided by the quotient of the $b
$a% $b modulo $a divided by the remainder of the $b
Increment/decrement operator
Operator name Result
+ + $a the value of the pre-add $a plus one, and then proceed
$a + + after adding a $a value to the first operation, after adding a
--$a the value of the pre-minus $a minus one and then the operation
$a--the value of the post-minus $a is first operated, minus one
Instance:
<?php
echo $a =5+ "5th"; Output: 10
Echo 10%3; Output: 1
echo + + $a + +; Output: 20
Echo 5--$a; Output: 5
?>
Comparison operators
Operator name Result
$a = = $b equals TRUE if $ A equals $b
$a = = = $b Congruent TRUE if $ A equals $b and their type is the same
$a! = $b equal to TRUE if $ A is not equal to $b
$a <> $b equal to TRUE if $ A is not equal to $b
$a!== $b non-congruent TRUE if $ A is not equal to $b, or if they are of different types
$a < $b less than TRUE if $ A is strictly less than $b
$a > $b greater than TRUE if $ A is strictly $b
$a <= $b less than or equal to TRUE if $a is less than or equal to $b
$a >= $b greater than or equal to TRUE if $a is greater than or equal to $b
Another conditional operator is "? : "(or ternary) operator.
Instance:
<?php
Var_dump (0== "a"); Output: bool (TRUE)
Var_dump (0== "00"); Output: bool (TRUE)
Var_dump (0=== "00"); Output: bool (FALSE)
Var_dump (0<> "abc"); Output: bool (FALSE)
Var_dump (0!== "01"); Output: bool (TRUE)
$a = 10;
$b = 20;
$str = $a > $b? "True": "false";
Echo $str; Output: false
?>
logical operators
Operator name Result
$a and $b logic with true if $a and $b are true.
$a or $b logical or true if either $a or $b is true.
$a XOR $b different or TRUE if $a and $b are not simultaneously
! $a logic is not true if the $a is not true.
$a && $b logic with True if $a and $b are true.
$a | | $b logical OR True if either $a or $b is true.
Where and with &&, OR and | | is a two-way notation for the same logical operator.
Logical and logical or both are short-circuit operators. When the following logical expression is encountered, the PHP interpreter will not evaluate the expression on the right:
<?php
$a = 10;
if (false && (+ + $a));
echo $a; Output: 10
$b = 10;
if (true or (+ + $b));
Echo $b; Output: 10
?>
Bitwise operators
The bitwise operator allows you to set the bits specified in the integer number. If both the left and right arguments are strings, the bitwise operator will manipulate the ASCII value of the character.
Expression name Result
$a & $b Bitwise is set to 1 for both the $a and the 1 bits in the $b.
$a | $b bitwise or sets the bit in the $a or the $b as 1 to 1.
$a ^ $b Bitwise XOR will set the different bits in the $a and $b to 1.
~ $a bitwise is not set to 1 for bits 0 in the $a, and vice versa.
$a << $b left shifts the bits in the $a to the left $b times (each move represents "multiplied by 2").
$a >> $b right moves the bits in the $a to the right $b times (each move represents "divided by 2").
Other operators
String operators
There are two string operators. The first one is the join operator (".") ), which returns the string after its left and right arguments are concatenated. The second is the Join assignment operator (". ="), which attaches the right argument to the left argument.
Error suppression operator
In the most common database connection and file creation operations or when exceptions such as 0 are present, you can suppress the function error message output to the browser by using the @ symbol $a =@ (5/0)
External command execution
Use ' to run External system commands, note not single quotes, is the key below ESC
<?php
$out = ' dir c: ';
Print_r ($out);
? >//is not recommended for use
Instance:
<?php
$a = "Hello";
$a. = "world! "; Equivalent to: $a = $a. "World!";
echo $a; Output: Hello world!
$m = 3;
$m + = 5; Equivalent to: $m = $m +5;
Echo $m; Output: 8
$c = ($b = 4) + 5;
Echo $c; Output: 9
?>
Operator Precedence
The following table lists the precedence of operators from low to high.
Combining direction operators
Left
Left or
Left XOR
Left and
Right print
right = + = = *=/=. =%= &= |= ^= ~= <<= >>=
Left? :
Left | |
Left &&
Combining direction operators
Left |
Left ^
Left &
No = = = = = = =!==
No < <= > >=
Left << >>
Left +-.
Left */%
Right! ~ + +--(int) (float) (string) (array) (object) @
Right
No new
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