How Do I Add a Filter to Shortcode in WordPress?

Adding a filter to a shortcode can be a helpful way to customize the output of your shortcode. To add a filter, first identify the shortcode you want to filter and then add the following line of code to the shortcode:

filter_var( $atts, FILTER_VALIDATE_INT );

The $atts variable is where you will add the filter definitions. The FILTER_VALIDATE_INT filter allows you to specify a filter condition. The following example filters all posts with a title that is less than 10 characters long:

filter_var( $atts, FILTER_VALIDATE_INT, 10 );

The filter_var() function will return an array of array variables. The first element in the array is the name of the filter, and the second element is the filter condition.

In the example above, the FILTER_VALIDATE_INT filter condition is 10.