PHP Operators

PHP Operators

An operator is a symbol that manipulates one or more values, usually producing a new value in the process. Meanwhile, an expression in PHP is anything that evaluates to a value; this can be any combination of values, variables, operators, and functions. In the preceding example, $x + $y is an expression. Here are some more examples of expressions:
$x + $y + $z
$x -$y
$x 5
gettype( $test_var ) The values and variables that are used with an operator are known as operands .

Operator Types

Operators in PHP can be grouped into ten types, as follows:

Type Description
Arithmetic Perform common arithmetical operations such as addition and subtraction
Assignment Assign values to variables
Bitwise Perform operations on individual bits in an integer
Comparison Compare values in a Boolean fashion ( true or false is returned)
Error Control Affect error handling
Execution Cause execution of commands as though they were shell commands
Incrementing/Decrementing Increment or decrement a variable ’ s value
Logical Boolean operators such as and  or  and not that can be used to include or exclude
String Concatenates (joins together) strings (there ’ s only one string operator)
Array Perform operations on arrays

The Assignment Operator

You have met the assignment operator each time we have initialized a variable. It consists of the single character =. The assignment operator takes the value of its right-hand operand and assigns it to its left-hand operand:

$name =”matt”;

The variable $name now contains the string “matt”. Interestingly, this construct is an expression. It might look at first glance that the assignment operator simply changes the variable $name without producing a value, but in fact, a statement that uses the assignment operator always resolves to a copy of the value of the right operand. Thus                print ( $name = “matt” );

prints the string “matt” to the browser in addition to assigning “matt” to $name.

For example,

$x = 4;

$x += 4; // $x now equals 8 is equivalent to $x = 4;

$x = $x + 4; // $x now equals 8

There is an assignment operator for each of the arithmetic operators and one for the concatenation operator.

Assignment Operators
Operator Example Equivalent to
+= $x += 5 $x = $x + 5
− = $x − = 5 $x = $x − 5
/= $x /= 5 $x = $x / 5
*= $x *= 5 $x = $x *5
%= $x%=5 $x = $x % 5
.= $x .= “test” $x = $x” test”

Arithmetic Operators

The arithmetic operators do exactly what you would expect. The addition operator adds the right operand to the left operand. The subtraction operator subtracts the right-hand operand from the left. The division operator divides the left-hand operand by the right. The multiplication operator multiplies the left-hand operand by the right. The modulus operator returns the remainder of the left operand divided by the right.

Arithmetic Operators
Operator Name Example Result
+ Addition 10+3 13
Subtraction 10−3 7
/ Division 10/3 3.3333333333333
* Multiplication 10*3 30
% Modulus 10%3 1

The Concatenation Operator

The concatenation operator is a single dot. Treating both operands as strings, it appends the right-hand operand to the left. So