add_action vs add_filter: What’s the Difference?

add_action is used to add code to WordPress. This code can be executed when a specific event or hook occurs. For example, you could use add_action to add a custom message to the end of every post, or to redirect users to a different page after they log in.

add_filter is used to modify the output of a function or filter in WordPress. This means that you can change the way that WordPress does something, such as the way that it formats dates or the way that it displays images.

Here is a table summarizing the key differences between add_action and add_filter:

Feature	add_action	add_filter
What it does	Adds code	Modifies the output of a function
Returns	Nothing	The modified output of the function
When to use it	When you want to add additional code to be executed	When you want to change the output of a function

Here are some examples of how add_action and add_filter can be used:

• To add a custom message to the end of every post, you could use the following code:

add_action('the_content', 'my_custom_message');

function my_custom_message() {
  echo '<p>This is a custom message.</p>';
}

• To change the way that WordPress formats dates, you could use the following code:

add_filter('date_format', 'my_custom_date_format');

function my_custom_date_format($format) {
  return 'Y-m-d';
}

Thank you for reading…