When you start developing for WordPress, understanding PHP variables and data types becomes essential. Whether you’re building themes, plugins, or just tweaking your site, variables are the building blocks you’ll use constantly. In this article, we’ll break down what variables are, how they work in PHP, and why data types matter. (If you don’t know about PHP and its syntax, study this first.)
What is a Variable?
In PHP, a variable is like a container where you can store data, such as numbers, text, or even complex information like arrays. Once stored, you can use this data throughout your code. PHP variables always start with a dollar sign ($), followed by the variable name. Example:
<?php $greeting = "Hello, WordPress!"; ?>
Here, $greeting holds the string "Hello, WordPress!". Later in your code, you can use $greeting it wherever you want to display or manipulate this message.
Basic Rules for Variable Names
-
Variable names must start with a letter (
a-z,A-Z) or an underscore (_). -
After the first character, numbers (
0-9) are allowed. -
Variable names are case-sensitive (
$greetingand$Greetingare different).
Example:
<?php $Name = "Alice"; $name = "Bob"; echo $Name; // Output: Alice echo $name; // Output: Bob ?>
PHP Data Types
Every variable in PHP has a type of data it holds. PHP is a loosely typed language, meaning you don’t have to declare the type when you create a variable — PHP figures it out automatically. Let’s go over the most common data types you’ll use in WordPress development.
1. String
A string is a sequence of characters, like text.
Example:
<?php $title = "Welcome to my WordPress site!"; ?>
2. Integer
An integer is a whole number (no decimals).
Example:
<?php $numb = 458; ?>
You’ll use integers for things like post IDs, user IDs, or any counting system.
3. Float (Double)
A float is a number with a decimal point.
Example:
<?php $numb = 458.75; ?>
When handling WooCommerce products or custom pricing features, floats are your friend.
4. Boolean
A boolean can only be TRUE or FALSE. It’s perfect for things like checking if a user is logged in, or if a post is published.
Example:
<?php $is_home = true; ?>
Booleans help you control the logic and flow of your WordPress plugins or themes.
5. Array
An array stores multiple values in one variable.
Example:
<?php
$categories = array("News", "Tutorials", "Reviews");
?>
Arrays are very common in WordPress, especially when dealing with things like taxonomies, settings, or custom queries.
6. Object
An object is a complex data type that represents an instance of a class.
In WordPress, when you work with posts or users through PHP, you often get objects.
Example:
<?php $post = get_post(42); echo $post->post_title; ?>
Here, get_post() retrieves a post object, and you can access its properties like post_title.
Declaring Multiple Variables
You can declare multiple variables at once to keep your code organized.
Example:
<?php $author = "Jane Doe"; $post_count = 7; $is_editor = true; ?>
This becomes really useful inside WordPress templates or plugin logic.
Type Casting
Sometimes, you may want to force a variable to be a specific type. This is called type casting.
Example:
<?php $views = "100"; $views = (int) $views; // Casts to integer ?>
Type casting is handy when you’re pulling data from the database where values might be stored as strings.
Conclusion
Understanding variables and data types is the first big step toward mastering PHP for WordPress development. Variables let you store and reuse information, while data types make sure you use the right kind of data for the right job.
In WordPress, you’ll find yourself working with variables all the time: setting options, building queries, customizing templates, and more. Take your time to get comfortable with them — it’s the foundation you’ll build on in every project.