Filter hooks in Wordpress - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a filter hook in WordPress?

A filter hook lets you change data before WordPress uses or shows it. It’s like a checkpoint where you can edit text, options, or content.

beginner

How do you add a filter hook in WordPress?

Use the add_filter() function with the filter name, your function name, priority, and number of arguments.

beginner

What does the callback function in a filter hook do?

It receives data, changes it if needed, and returns the new data back to WordPress.

intermediate

Why use filter hooks instead of changing core WordPress files?

Filter hooks keep your changes safe during updates and make your code easier to manage and share.

intermediate

What happens if a filter callback does not return a value?

WordPress will get no data back, which can break the site or cause unexpected results. Always return the modified or original data.

Which function is used to add a filter hook in WordPress?

A apply_filter()

B add_filter()

C add_action()

D register_filter()

The correct function to add a filter hook is add_filter(). add_action() is for action hooks.

What must a filter callback function always do?

A Return the filtered data

B Print the filtered data

C Modify global variables

D Call add_filter() again

A filter callback must return the filtered data so WordPress can use it.

When is a filter hook applied in WordPress?

A Only in the admin dashboard

B After data is saved

C Only during plugin activation

D Before data is saved or displayed

Filter hooks run before data is saved or shown, allowing you to change it.

What does the priority parameter in add_filter() control?

A Order in which filters run

B Number of arguments passed

C Whether the filter is active

D The filter’s name

Priority controls the order filters run; lower numbers run first.

Can multiple filter hooks be added to the same filter name?

A No, filters must have unique names

B No, only one filter per name

C Yes, they run in priority order

D Yes, but only the last one runs

Multiple filters can attach to the same filter name and run in order by priority.

Explain how filter hooks work in WordPress and why they are useful.

Think about how you can change text or options without editing WordPress files.

Describe the steps to create a custom filter hook in WordPress.

Focus on the function and how it connects to WordPress.