Basic introduction to php operators

PHP Arithmetic Operator

##OperatorNameExampleResult##+-*/%

PHP Increment/Decrease Operator

Addition	$x + $y	Sum of $x and $y
Subtraction	$x - $y	Difference between $x and $y
Multiplication	$x * $y	$x and $y Product
Division	$x / $y	Quotient of $x and $y
Modulus	$x % $y	$x is the remainder after dividing $y

Operator	Name	Description
++$x	increments before	$x increments by one, then returns $x
$x++	increments after	Return $x, then $x increases by one and increments
--$x	decrements before it	$x decreases by one , then return $x
$x--	and then decrement	Return $x, then $x decrement by one

PHP assignment operator

PHP assignment operator is used to write values ​​to variables.

The basic assignment operator in PHP is "=". This means that the right-hand assignment expression sets the value of the left-hand operand.

##x *= yx = x * yMultiplyx /= yx = x / ydividex % = yx = x % ymodulus

PHP comparison operators

PHP comparison operators are used to compare two values ​​(numbers or strings):

Assignment	is equivalent to	Description
x = y	x = y	The right-hand expression sets the value for the left-hand operand.
x += y	x = x + y	plus
x -= y	x = x - y	minus

Operator	Name	Example	Result
==	equals	$x == $y	Returns true if $x is equal to $y.
===	Congruent (identical)	$x === $y	If $x is equal to $y and they are of the same type, return true.
!=	is not equal to	$x != $y	If $x is not equal to $y, return true.
<>	is not equal to	$x <> $y	If $x is not equal to $ y, returns true.
!==	Not congruent (completely different)	$x !== $y	If $x is not If equal to $y and their types are not the same, return true.
>	is greater than	$x > $y	Returns true if $x is greater than $y.
<	is greater than	$x < $y	Returns true if $x is less than $y.
>=	Greater than or equal to	$x >= $y	If $x is greater than or equal to $ y, returns true.

PHP Logical Operator

Operator	Name	Example	Result
and	with	$x and $y	Returns true if both $x and $y are true.
or	or	$x or $y	If at least one of $x and $y is true, then Return true.
xor	XOR	$x xor $y	If there is and only one of $x and $y is true, returns true.
&&	&	$x && $y	If both $x and $y are true, return true .
||	or	$x || $y	If at least one of $x and $y is true , then returns true.
!	Not	!$x	Returns true if $x is not true.

The following table lists the operators in order of precedence from high to low. Operators in the same line have the same precedence, and the direction in which they are combined determines the order of evaluation.

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Operator precedence

Combining direction	Operator	Additional information
		array()
right	++ -- ~ (int) (float) (string) (array) (object) (bool) @	Type and increment/decrement
none	instanceof	type
right	!	Logical operator
left	* / %	Arithmetic operator
left	+ - .	Arithmetic operators and string operators
left	<< >>	Bitwise operators
None	== != === !== <>	Comparison operators
left	&	Bitwise operators and references
left	^	Bit operator
left	|	Bit operator
left	&&	Logical operator
left	||	Logical operator
left	? :	ternary operator
right	= += -= *= /= .= %= &= |= ^= <<= >>= =>	Assignment Operator
left	and	logical operator
left	xor	logical Operator
left	or	logical operator
left	,	多

is used everywhere. For operators with the same precedence, the left associative direction means that the evaluation will be from left to right, and the right associative direction means on the contrary. It is possible that an operator with the same precedence without associative direction cannot be combined with itself. For example, in PHP 1 < 2 > 1 is an illegal statement, but 1 <= 1 == 1 is not. Because the T_IS_EQUAL operator has a lower priority than the T_IS_SMALLER_OR_EQUAL operator.

When doing operator problems, be sure to pay attention to priority issues, as shown in the following example:

For $f, because = has a higher priority than or, so this formula assigns a value to $f first and then performs the or operation, so the result is false

php ternary operator:

Basic syntax:

Expression 1 ? Expression 2 ： Expression 3                  

Rule: If expression If the operation result of 1 is true, then the value of expression 2 is taken, otherwise, the value of expression 3 is taken.

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PHP String Operator:

In PHP, there is only one string operator.

The concatenation operator (.) is used to concatenate two string values.

The following example demonstrates how to concatenate two string variables together:

Example

$txt1="Hello world!";
$txt2="What a nice day!";
echo $txt1 . " " . $txt2;
? >

The above code will output: Hello world! What a nice day!

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