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📖 PHP Operators

Operators are symbols used in expressions to manipulate variables and literals. They help create more complex expressions by combining or comparing values.

For example

area = length * width
circumference = 2 * pi * radius
amount = 500

Example

<?php
    // Calculating the Area of a Rectangle

    // assign values to variables
    $length = 2;
    $width = 4;

    // perform arithmetic operation
    $area = $length * $width;

    // concatenate output to html
    echo "<p>The area of the rectangle is " . $area . ".</p>";
?>

The example code above would output the following HTML.

<p>The area of the rectangle is 8.</p>

Operators

Arithmetic

[ + ] Addition

[ - ] Subtraction/Negation

[ * ] Multiplication

[ / ] Division

[ % ] Modulus

[ ++ ] Increment (Prefix/Postfix)

[ -- ] Decrement (Prefix/Postfix)

Assignment

[ = ] Assigns value to a variable

[ += ] Adds and assigns value

[ -= ] Subtracts and assigns value

[ *= ] Multiplies and assigns value

[ /= ] Divides and assigns value

[ %= ] Modulus and assigns remainde

Comparison

[ == ] Equal

[ != ] Not equal

[ > ] Greater than

[ < ] Less than

[ >= ] Greater than or equal to

[ <= ] Less than or equal to

Logical

[ && ] AND

[ || ] OR

[ ! ] NOT

String

[ . ] Concatenation

[ .= ] Concatenation and assignment

Example


<?php
    // assignment operator
    $myNumber = 24;

    // arithmetic operator
    $myMultiplication = 5 * 7;
    $myAddition = 5 + $myNumber;

    // comparison operator
    $isGreater = $myAddition >= 10;

    // logical operator
    $isTrue = $myAddition && $myNumber;

    // concatenation operator
    $myColor = "Blue";
    $myPoem = "Little boy " . $myColor . " come blow your horn.";

    /* comparison and logical operators are generally used in expressions */
?>

Operator Precedence

Operator precedence defines the order in which a series of calculations are executed. If an expression contains multiple operations at the same level, they are executed from left to right.

Operations enclosed in parentheses
Logical NOT (!), Increment (++), and Decrement (--)
Multiplication (*), Division (/), Modulus (%)
Addition (+), Subtraction (-), Concatenation (.)

Formatting Numbers

PHP provides built-in functions for formatting numbers.

`round(number, decimal_places)`

Rounds the number to the specified decimal places.
Number can be a literal or a variable.
If decimal places are omitted, 0 is assumed.

`number_format(number, decimal_places)`

Similar to round, but adds commas for thousands.
If decimal places are omitted, 0 is assumed.

Example

<?php
    // Formatting a Product Invoice

    // assign values to variables
    $price = 2.99;
    $quantity = 2;
    $taxRate = 0.08;

    // perform arithmetic operations
    $subTotal = $price * $quantity;
    $tax = $subTotal * $taxRate;
    $tax = number_format($tax, 2); // format tax to 2 decimal places
    $total = $subTotal + $tax;

    // format output to HTML
    echo '<table>
    <caption>Product Invoice</caption>
    <thead>
        <tr>
            <th>Description</th>
            <th>Quantity</th>
            <th>Unit Price</th>
            <th>Cost</th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>Widgets</td>
            <td style="text-align: center;">' . $quantity . '</td>
            <td style="text-align: center;">$' . $price . '</td>
            <td style="text-align: center;">$' . $subTotal . '</td>
        </tr>
        <tr>
            <td>Tax</td>
            <td style="text-align: center;">&nbsp;</td>
            <td style="text-align: center;">' . $taxRate . '</td>
            <td style="text-align: center;">$' . $tax . '</td>
        </tr>
        <tr>
            <td>Total</td>
            <td style="text-align: center;">&nbsp;</td>
            <td style="text-align: center;">&nbsp;</td>
            <td style="text-align: center;">$' . $total . '</td>
        </tr>
    </tbody>
    </table>';
?>

HTML output

Product Invoice
Description	Quantity	Unit Price	Cost
Widgets	2	$2.99	$5.98
Tax		.08	$.48
Total			$6.46