add_action and add_filter in Wordpress - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the add_action function do in WordPress?

add_action lets you run your custom code at specific points during WordPress execution. It "hooks" your function to an event.

beginner

What is the purpose of add_filter in WordPress?

add_filter lets you modify data before WordPress uses or shows it. It "filters" content by running your function on it.

intermediate

How do add_action and add_filter differ in their use?

add_action runs code at certain events without changing data. add_filter runs code that changes or returns data.

intermediate

What parameters does add_action accept?

<p><code>add_action</code> takes: the hook name (string), your function name (callable), priority (number, default 10), and accepted args count (default 1).</p>

intermediate

Why is priority important in add_action and add_filter?

Priority decides the order your function runs if many functions hook to the same event. Lower numbers run first.

What does add_filter primarily do in WordPress?

A Runs code to change data before output

B Runs code only once on page load

C Adds a new admin menu

D Deletes a post automatically

add_filter modifies data by running your function on it before WordPress uses or shows it.

Which parameter is NOT part of add_action?

A Hook name

B Function name

C Database connection

D Priority

add_action does not take a database connection parameter.

If you want your function to run after others on the same hook, what should you do?

A Use a higher priority number

B Use a lower priority number

C Use <code>remove_action</code>

D Change the function name

Higher priority numbers run later, so your function runs after others.

Which hook type lets you add extra HTML to a page without changing data?

A Database hook

B Action hook

C Filter hook

D Security hook

Action hooks let you run code at points in WordPress, like adding HTML output.

What must your function do when used with add_filter?

A Call <code>exit()</code>

B Echo the data directly

C Delete the data

D Return the modified data

Filter functions must return the data, usually modified, so WordPress can use it.

Explain how add_action and add_filter work in WordPress and when to use each.

Think about actions as events and filters as data changes.

Describe the role of priority in add_action and add_filter and how it affects function execution order.

Imagine a queue where priority decides who goes first.