Arithmetic operator in php

PHP Arithmetic Operators

Summary: in this tutorial, you will learn about the arithmetic operators including addition, subtraction, multiplication, division, exponentiation, and modulo to perform arithmetic operations.

Introduction to PHP arithmetic operators

PHP provides you with common arithmetic operators that allow you to perform addition, subtraction, multiplication, division, exponentiation, and modulus operations.

The arithmetic operators require numeric values. If you apply an arithmetic operator to non-numeric values, it’ll convert them to numeric values before performing the arithmetic operation.

The following table illustrates the arithmetic operators in PHP:

Operator	Name	Example	Description
+	Addition	$x * $y	Return the sum of $x and $y
–	Substration	$x – $y	Return the difference of $x and $y
*	Multiplication	$x * $y	Return the product of $x and $y
/	Division	$x / $y	Return the quotient of $x and $y
%	Modulo	$x % $y	Return the remainder of $x divided by $y
**	Exponentiation	$x ** $y	Return the result of raising $x to the $y ‘th power.

PHP arithmetic operator examples

The following example uses the arithmetic operators:

 $x = 20; $y = 10; // add, subtract, and multiplication operators demo echo $x + $y; // 30 echo $x - $y; // 10 echo $x * $y; // 200 // division operator demo $z = $x / $y; // modulo demo $y = 15; echo $x % $y; // 5Code language: HTML, XML (xml)

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PHP Operators

Operators are used to perform operations on variables and values.

PHP divides the operators in the following groups:

• Arithmetic operators
• Assignment operators
• Comparison operators
• Increment/Decrement operators
• Logical operators
• String operators
• Array operators
• Conditional assignment operators

PHP Arithmetic Operators

The PHP arithmetic operators are used with numeric values to perform common arithmetical operations, such as addition, subtraction, multiplication etc.

Operator	Name	Example	Result	Show it
+	Addition	$x + $y	Sum of $x and $y	Try it »
—	Subtraction	$x — $y	Difference of $x and $y	Try it »
*	Multiplication	$x * $y	Product of $x and $y	Try it »
/	Division	$x / $y	Quotient of $x and $y	Try it »
%	Modulus	$x % $y	Remainder of $x divided by $y	Try it »
**	Exponentiation	$x ** $y	Result of raising $x to the $y’th power	Try it »

PHP Assignment Operators

The PHP assignment operators are used with numeric values to write a value to a variable.

The basic assignment operator in PHP is «=». It means that the left operand gets set to the value of the assignment expression on the right.

Assignment	Same as.	Description	Show it
x = y	x = y	The left operand gets set to the value of the expression on the right	Try it »
x += y	x = x + y	Addition	Try it »
x -= y	x = x — y	Subtraction	Try it »
x *= y	x = x * y	Multiplication	Try it »
x /= y	x = x / y	Division	Try it »
x %= y	x = x % y	Modulus	Try it »

PHP Comparison Operators

The PHP comparison operators are used to compare two values (number or string):

Operator	Name	Example	Result	Show it
==	Equal	$x == $y	Returns true if $x is equal to $y	Try it »
===	Identical	$x === $y	Returns true if $x is equal to $y, and they are of the same type	Try it »
!=	Not equal	$x != $y	Returns true if $x is not equal to $y	Try it »
<>	Not equal	$x <> $y	Returns true if $x is not equal to $y	Try it »
!==	Not identical	$x !== $y	Returns true if $x is not equal to $y, or they are not of the same type	Try it »
>	Greater than	$x > $y	Returns true if $x is greater than $y	Try it »
	Less than	$x < $y	Returns true if $x is less than $y	Try it »
>=	Greater than or equal to	$x >= $y	Returns true if $x is greater than or equal to $y	Try it »
	Less than or equal to	$x	Returns true if $x is less than or equal to $y	Try it »
	Spaceship	$x $y	Returns an integer less than, equal to, or greater than zero, depending on if $x is less than, equal to, or greater than $y. Introduced in PHP 7.	Try it »

PHP Increment / Decrement Operators

The PHP increment operators are used to increment a variable’s value.

The PHP decrement operators are used to decrement a variable’s value.

Operator	Name	Description	Show it
++$x	Pre-increment	Increments $x by one, then returns $x	Try it »
$x++	Post-increment	Returns $x, then increments $x by one	Try it »
—$x	Pre-decrement	Decrements $x by one, then returns $x	Try it »
$x—	Post-decrement	Returns $x, then decrements $x by one	Try it »

PHP Logical Operators

The PHP logical operators are used to combine conditional statements.

Operator	Name	Example	Result	Show it
and	And	$x and $y	True if both $x and $y are true	Try it »
or	Or	$x or $y	True if either $x or $y is true	Try it »
xor	Xor	$x xor $y	True if either $x or $y is true, but not both	Try it »
&&	And	$x && $y	True if both $x and $y are true	Try it »
||	Or	$x || $y	True if either $x or $y is true	Try it »
!	Not	!$x	True if $x is not true	Try it »

PHP String Operators

PHP has two operators that are specially designed for strings.

Operator	Name	Example	Result	Show it
.	Concatenation	$txt1 . $txt2	Concatenation of $txt1 and $txt2	Try it »
.=	Concatenation assignment	$txt1 .= $txt2	Appends $txt2 to $txt1	Try it »

PHP Array Operators

The PHP array operators are used to compare arrays.

Operator	Name	Example	Result	Show it
+	Union	$x + $y	Union of $x and $y	Try it »
==	Equality	$x == $y	Returns true if $x and $y have the same key/value pairs	Try it »
===	Identity	$x === $y	Returns true if $x and $y have the same key/value pairs in the same order and of the same types	Try it »
!=	Inequality	$x != $y	Returns true if $x is not equal to $y	Try it »
<>	Inequality	$x <> $y	Returns true if $x is not equal to $y	Try it »
!==	Non-identity	$x !== $y	Returns true if $x is not identical to $y	Try it »

PHP Conditional Assignment Operators

The PHP conditional assignment operators are used to set a value depending on conditions:

Operator	Name	Example	Result	Show it
?:	Ternary	$x = expr1 ? expr2 : expr3	Returns the value of $x. The value of $x is expr2 if expr1 = TRUE. The value of $x is expr3 if expr1 = FALSE	Try it »
??	Null coalescing	$x = expr1 ?? expr2	Returns the value of $x. The value of $x is expr1 if expr1 exists, and is not NULL. If expr1 does not exist, or is NULL, the value of $x is expr2. Introduced in PHP 7	Try it »

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Арифметические операторы

Помните школьные основы арифметики? Описанные ниже операторы работают так же.

Арифметические операции

Пример	Название	Результат
-$a	Отрицание	Смена знака $a .
$a + $b	Сложение	Сумма $a и $b .
$a — $b	Вычитание	Разность $a и $b .
$a * $b	Умножение	Произведение $a и $b .
$a / $b	Деление	Частное от деления $a на $b .
$a % $b	Деление по модулю	Целочисленный остаток от деления $a на $b .
$a ** $b	Возведение в степень	Результат возведения $a в степень $b . Добавлен в PHP 5.6.

Операция деления («/») возвращает число с плавающей точкой, кроме случая, когда оба значения являются целыми числами (или строками, которые преобразуются в целые числа), которые делятся нацело — в этом случае возвращается целое значение.

При делении по модулю операнды преобразуются в целые числа (удалением дробной части) до начала операции.

Результат операции остатка от деления % будет иметь тот же знак, что и делимое — то есть, результат $a % $b будет иметь тот же знак, что и $a . Например:

echo ( 5 % 3 ). «\n» ; // выводит 2
echo ( 5 % — 3 ). «\n» ; // выводит 2
echo (- 5 % 3 ). «\n» ; // выводит -2
echo (- 5 % — 3 ). «\n» ; // выводит -2

Также вы можете ознакомиться с разделом документации Математические функции.

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Operators

An operator is something that takes one or more values (or expressions, in programming jargon) and yields another value (so that the construction itself becomes an expression).

Operators can be grouped according to the number of values they take. Unary operators take only one value, for example ! (the logical not operator) or ++ (the increment operator). Binary operators take two values, such as the familiar arithmetical operators + (plus) and — (minus), and the majority of PHP operators fall into this category. Finally, there is a single ternary operator, ? : , which takes three values; this is usually referred to simply as «the ternary operator» (although it could perhaps more properly be called the conditional operator).

A full list of PHP operators follows in the section Operator Precedence. The section also explains operator precedence and associativity, which govern exactly how expressions containing several different operators are evaluated.

User Contributed Notes 9 notes

of course this should be clear, but i think it has to be mentioned espacially:

’cause || has got a higher priority than and, but less than &&

of course, using always [ && and || ] or [ AND and OR ] would be okay, but than you should at least respect the following:

the first code will set $a to the result of the comparison $b with $c, both have to be true, while the second code line will set $a like $b and THAN — after that — compare the success of this with the value of $c

maybe usefull for some tricky coding and helpfull to prevent bugs 😀

Operator are used to perform operation.

Operator are mainly divided by three groups.
1.Uniary Operators that takes one values
2.Binary Operators that takes two values
3.ternary operators that takes three values

Operator are mainly divided by three groups that are totally seventeen types.
1.Arithmetic Operator
+ = Addition
— = Subtraction
* = Multiplication
/ = Division
% = Modulo
** = Exponentiation

2.Assignment Operator
= null coalescing

14.Clone new Operator
clone new = clone new

16.yield Operator
yield = yield

17.print Operator
print = print

Other Language books’ operator precedence section usually include «(» and «)» — with exception of a Perl book that I have. (In PHP «<" and ">» should also be considered also). However, PHP Manual is not listed «(» and «)» in precedence list. It looks like «(» and «)» has higher precedence as it should be.

Note: If you write following code, you would need «()» to get expected value.

$bar = true ;
$str = «TEST» . ( $bar ? ‘true’ : ‘false’ ) . «TEST» ;
?>

Without «(» and «)» you will get only «true» in $str.
(PHP4.0.4pl1/Apache DSO/Linux, PHP4.0.5RC1/Apache DSO/W2K Server)
It’s due to precedence, probably.

The variable symbol ‘$’ should be considered as the highest-precedence operator, so that the variable variables such as $$a[0] won’t confuse the parser. [http://www.php.net/manual/en/language.variables.variable.php]

If you use «AND» and «OR», you’ll eventually get tripped up by something like this:

$this_one = true ;
$that = false ;
$truthiness = $this_one and $that ;
?>

Want to guess what $truthiness equals?

If you said «false» . it’s wrong!

«$truthiness» above has the value «true». Why? «=» has a higher precedence than «and». The addition of parentheses to show the implicit order makes this clearer:

( $truthiness = $this_one ) and $that ;
?>

If you used «&&» instead of and in the first code example, it would work as expected and be «false».

This also works to get the correct value, as parentheses have higher precedence than » default»>$truthiness = ( $this_one and $that );
?>

Note that in php the ternary operator ?: has a left associativity unlike in C and C++ where it has right associativity.

You cannot write code like this (as you may have accustomed to in C/C++):

$a = 2 ;
echo (
$a == 1 ? ‘one’ :
$a == 2 ? ‘two’ :
$a == 3 ? ‘three’ :
$a == 4 ? ‘four’ : ‘other’ );
echo «\n» ;
// prints ‘four’
?>

You need to add brackets to get the results you want:

echo ( $a == 1 ? ‘one’ :
( $a == 2 ? ‘two’ :
( $a == 3 ? ‘three’ :
( $a == 4 ? ‘four’ : ‘other’ ) ) ) );
echo «\n» ;
//prints ‘two’
?>

The scope resolution operator . which is missing from the list above, has higher precedence than [], and lower precedence than ‘new’. This means that self::$array[$var] works as expected.

A quick note to any C developers out there, assignment expressions are not interpreted as you may expect — take the following code ;-

$a =array( 1 , 2 , 3 );
$b =array( 4 , 5 , 6 );
$c = 1 ;

print_r ( $a ) ;
?>

This will output;-
Array ( [0] => 1 [1] => 6 [2] => 3 )
as if the code said;-
$a[1]=$b[2];

Under a C compiler the result is;-
Array ( [0] => 1 [1] => 5 [2] => 3 )
as if the code said;-
$a[1]=$b[1];

It would appear that in php the increment in the left side of the assignment is processed prior to processing the right side of the assignment, whereas in C, neither increment occurs until after the assignment.

A variable is a container that contain different types of data and the operator operates a variable correctly.

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