PHP has a set of math functions that allows you to perform mathematical tasks on numbers.
PHP pi() Function
The pi() function returns the value of PI:
Example
<?php
echo(pi()); // returns 3.1415926535898
?>PHP min() and max() Functions
The min() and max() functions can be used to find the lowest or highest value in a list of arguments:
Example
<?php
echo(min(0, 150, 30, 20, -8, -200)); // returns -200
echo(max(0, 150, 30, 20, -8, -200)); // returns 150
?>PHP abs() Function
The abs() function returns the absolute (positive) value of a number:
Example
<?php
echo(abs(-6.7)); // returns 6.7
?>PHP sqrt() Function
The sqrt() function returns the square root of a number:
Example
<?php
echo(sqrt(64)); // returns 8
?>PHP round() Function
The round() function rounds a floating-point number to its nearest integer:
Example
<?php
echo(round(0.60)); // returns 1
echo(round(0.49)); // returns 0
?>Random Numbers
The rand() function generates a random number:
Example
<?php
echo(rand());
?>To get more control over the random number, you can add the optional min and max parameters to specify the lowest integer and the highest integer to be returned.
For example, if you want a random integer between 10 and 100 (inclusive), use rand(10, 100):
Example
<?php
echo(rand(10, 100));
?>Constants are like variables except that once they are defined they cannot be changed or undefined.
PHP Constants
A constant is an identifier (name) for a simple value. The value cannot be changed during the script.
A valid constant name starts with a letter or underscore (no $ sign before the constant name).
Note: Unlike variables, constants are automatically global across the entire script.
Create a PHP Constant
To create a constant, use the define() function.
Syntax
define(name, value, case-insensitive)Parameters:
- name: Specifies the name of the constant
- value: Specifies the value of the constant
- case-insensitive: Specifies whether the constant name should be case-insensitive. Default is false
Example
Create a constant with a case-sensitive name:
<?php
define("GREETING", "Welcome to W3Schools.com!");
echo GREETING;
?>Example
Create a constant with a case-insensitive name:
<?php
define("GREETING", "Welcome to W3Schools.com!", true);
echo greeting;
?>PHP Constant Arrays
In PHP7, you can create an Array constant using the define() function.
Example
Create an Array constant:
<?php
define("cars", [
"Alfa Romeo",
"BMW",
"Toyota"
]);
echo cars[0];
?>Constants are Global
Constants are automatically global and can be used across the entire script.
Example
This example uses a constant inside a function, even if it is defined outside the function:
<?php
define("GREETING", "Welcome to W3Schools.com!");
function myTest() {
echo GREETING;
}
myTest();
?>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 - Subtraction $x - $y Difference of $x and $y * Multiplication $x * $y Product of $x and $y / Division $x / $y Quotient of $x and $y % Modulus $x % $y Remainder of $x divided by $y ** Exponentiation $x ** $y Result of raising $x to the $y'th power
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 x += y x = x + y Addition x -= y x = x - y Subtraction x *= y x = x * y Multiplication x /= y x = x / y Division x %= y x = x % y Modulus
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 === Identical $x === $y Returns true if $x is equal to $y, and they are of the same type != Not equal $x != $y Returns true if $x is not equal to $y <> Not equal $x <> $y Returns true if $x is not equal to $y !== Not identical $x !== $y Returns true if $x is not equal to $y, or they are not of the same type > Greater than $x > $y Returns true if $x is greater than $y < Less than $x < $y Returns true if $x is less than $y >= Greater than or equal to $x >= $y Returns true if $x is greater than or equal to $y <= Less than or equal to $x <= $y Returns true if $x is less than or equal to $y <=> 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 $y. Introduced in PHP 7.
PHP Increment / Decrement Operators
The PHP increment operators are used to increment a variable's value.
The PHP decrement operators are used to decrement a variable's value.
Operator Name Description Show it ++$x Pre-increment Increments $x by one, then returns $x $x++ Post-increment Returns $x, then increments $x by one --$x Pre-decrement Decrements $x by one, then returns $x $x-- Post-decrement Returns $x, then decrements $x by one
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 or Or $x or $y True if either $x or $y is true xor Xor $x xor $y True if either $x or $y is true, but not both && And $x && $y True if both $x and $y are true || Or $x || $y True if either $x or $y is true ! Not !$x True if $x is not true
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 .= Concatenation assignment $txt1 .= $txt2 Appends $txt2 to $txt1
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 == Equality $x == $y Returns true if $x and $y have the same key/value pairs === Identity $x === $y Returns true if $x and $y have the same key/value pairs in the same order and of the same types != Inequality $x != $y Returns true if $x is not equal to $y <> Inequality $x <> $y Returns true if $x is not equal to $y !== Non-identity $x !== $y Returns true if $x is not identical to $y
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 ?? 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
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