PHP OR Operator

The PHP OR operator has two renditions: either || or or. Both of these are useful logical operators when you want to introduce flexible conditions in your PHP script. They’re especially helpful within if statements where you want to check if at least one condition is true to execute your code.

Let’s dive into how || and or work, their differences, and some practical examples.

Syntax Using || and or in PHP

PHP supports two ways to express the OR logical operator: || (double vertical bar) or or (keyword). Here’s the syntax for both:

if (condition1 || condition2) {
    // Executes if any one of them is true
}

or

if (condition1 or condition2) {
    // Executes if either condition is true
}

Both || and or can be used interchangeably, but || has a higher precedence than or. This means that in complex conditions, || gets evaluated before or. This can lead to different outcomes based on how your code works. Knowing this difference will help you avoid mistakes in complicated statements.

Anyway, the following table shows you the possible outputs based on different combinations of condition1 and condition2 when using the or operator (or keyword or ||). Here’s a simple table:

  So, let's move on to the next section to understand the difference between || and or in PHP.  

Difference Between || and or in PHP

PHP treats || and or as synonyms, meaning they both return true if at least one condition is met. However, || has a higher precedence than or, so in a chain of operations, it’s evaluated first.

Here is an example: 

$a = true || false; // $a is true
$b = true or false; // $b is true

In the above example, $a evaluates to true because || has a higher precedence over other operators, whereas or behaves differently when used in a complex condition. This difference becomes crucial when these logical operators are combined in a single statement.

So, how is the or operator evaluated in PHP? Let's move to the section below to understand that.  

How PHP Evaluates the OR Operator

The PHP OR operator, whether using || or or, is like a team player. It checks multiple conditions and returns true if any one of them is true. If all conditions are false, it evaluates to false.

For example:

$yes = true;
$no = false;
if ($yes || $no) {
    echo "This is all YES :)";
}

In this example, since $yes is true, the whole statement evaluates to true.

You can also combine multiple expressions simultaneously. Let’s move to the section below to see how this works.

Advanced Usage: Combining Conditions with OR

The OR operator can handle more complicated conditions by combining it with other operators. You can think of it as a checklist where you only need one box checked off to move forward.

Here is an example:

if ($userIsLoggedIn || ($userRole == "admin" && $canAccess == true)) {
    // Executes if the user is logged in OR if they're an admin and can access
}

In this code, the condition will evaluate as true if $userIsLoggedIn is true, or if both $userRole is “admin” and $canAccess is true.

Let's take a look at the following part to see how to write short-circuiting with or operator.

Short-Circuiting with the OR Operator

The OR operator has a feature called "short-circuiting," where it stops evaluating once it finds a true condition. This can save processing time, especially in cases involving complex conditions or heavy functions.

$isAuthorized = true;
$canEnter = $isAuthorized || checkAdditionalPermissions();

Because $isAuthorized is true, checkAdditionalPermissions() will not be executed. The effect of short-circuiting here is that PHP will skip evaluating conditions it knows are unnecessary, optimizing the code.

Example: Testing Form Submissions

Use of the OR operator is very common in form validation, where you might need to check that a certain field was filled out before processing the form.

$_POST["email"] = true; // Simulating a form submission
$is_email_existing = isset($_POST["email"]) || false;

echo $is_email_existing; // Outputs true

Here, isset($_POST["email"]) checks if the ‘email’ field exists in the form submission. If it does, PHP short-circuits OR and outputs true.

Wrapping Up

In PHP, the logical OR operator—|| and or—is integral for handling multiple conditions effectively. For higher precedence in complex expressions, use ||; remember that either of these operators can simplify decision-making in your code. With the right approach, you’ll be able to create powerful conditional statements that keep your PHP projects running smoothly.

Thank you for reading. Happy coding!