Introduction to WordPress Conditional Tags: A Comprehensive Guide

One of the most important advantages of WordPress is core scalability. For nearly a decade, WordPress users have been able to shape their websites through plugins and themes. (WordPress was first released in 2003, but plugins were launched in 2004 and themes in 2005.) To create such a solid infrastructure, WordPress includes many convenient subsystems (functions, classes, or entire APIs). One of them is "conditional tags", which allow our code to behave differently under specific circumstances.

In this series, we will learn about these conditional tags. In this article, we will start with the definition and importance of conditional tags. In the next sections, we'll introduce conditional tags with a description and some examples.

let us start!

What is a conditional tag?

In Codex, the description of conditional tags is as follows:

Conditional tags can be used in template files to change what content is displayed and how that content is displayed on a specific page, depending on which conditions the page matches.

You get the idea: In order for your code to use and/or change content, you use conditional tags and tell your code the type, status, and location of the content. Imagine your code talking to WordPress:

• Your code:Hey man, I need some help.
• WordPress:Of course, I’m all ears. what do you need?
• Your code: I will wrap these post titles with some DIVs, but I need to know if they are on the category archive page. Are these on the category archive page?
• WordPress: TRUE
• Your code: Hmm...what?
• WordPress:I mean yes.
• Your code:Awesome, thank you!
• WordPress: Goodbye!

So, in a nutshell, conditional labels are Boolean statements that, when used in if/else statements, guide your code to know where they are. They only return TRUE or FALSE, and your code only needs these two boolean values.

How to use conditional tags

Although conditional tags are a very important part of WordPress development, using them is very simple. Since they only return TRUE or FALSE, you can use them in if statements without any trouble. (Actually, there are three special conditional tags that return FALSE or a value, and we'll cover them in the next section, but you can also use them in if statements.)

Let’s understand how conditional tags work through a simple example:

<?php

if ( is_home() ) {

    _e( 'Welcome to my humble blog!', 'translation-domain' );

}

?>

do you understand? We’re using a conditional tag in an if statement and telling WordPress that if it’s the home page, this code will echo a somewhat dull welcome text. Actually it's not a big deal.

Let's take another example with some "cleaner" code:

<?php

// $author_check is TRUE or FALSE
$author_check = is_author( 'baris-unver' );

if ( $author_check ) {

    _e( 'Barış has some really good tutorials, along with a few cheesy ones!', 'translation-domain' );

}

?>

See what we did? We created a variable and defined the conditional label in it; so we can use the variable in the if statement. A piece of cake!

Example scenario using conditional tags

Believe me, there are countless situations when using conditional tags. I can immediately give you five scenarios where conditional tags can be used:

1. Suppose you are developing a social sharing plugin for WordPress and you want to give users the option to show and hide widgets under posts and pages. With a combination of is_single(), is_page() and is_singular() you can create a function that checks the user's plugin settings, for example on a hidden page widgets but display them under every page they are published.
2. Suppose you are developing a theme for a small company. You're working on the News page (Blog section of the theme) and you design a nice list of posts with thumbnails...but you know they'll forget or choose not to use thumbnails for some posts . This is where has_post_thumbnail() comes in handy: using it, your theme will check if the post doesn't have a thumbnail and show the default image.
3. Suppose you are creating an add-on plugin for a popular WordPress plugin. You need to detect if the main plugin is installed and in use, as this may cause problems if a novice user installs your plugin without using the main plugin. The solution is simple: using is_plugin_active() you can disable the plugin's functionality, and using is_plugin_inactive() you can show a warning in the admin area.
4. You have created a theme for another client who wants to upload images, PDF documents, and ZIP archives to their posts, but they also want all images to be displayed under each post. Simply using the conditional tag wp_attachment_is_image() will allow you to select an image and display it under the post.
5. Suppose you are making a plugin for a multi-author blog and you want to detect if a user's website has multiple authors. The conditional tag is_multi_author() gives you the answer.

in conclusion

As you can see, conditional tags are one of the easiest features to use in WordPress and one of the most important parts of theme and plugin development.

The purpose of this series is to introduce conditional tags, and we're just getting started. Over the next five articles, we'll cover 65 different condition tags, including descriptions, use cases, and examples.

See you in the next part!

The above is the detailed content of Introduction to WordPress Conditional Tags: A Comprehensive Guide. For more information, please follow other related articles on the PHP Chinese website!