WordPress Object Cheat Sheets

There are several objects in WordPress that we use all the time, namely $post, $comment and categories/tags. If you’re like me though, you never remember everything that’s in there, or the names of the values you want.

This cheat sheet will be a reference which you (and I) can refer to the next time you’re using one of the WordPress objects.

Quick Primer on Using Objects

If you haven’t used objects before or aren’t familiar with the syntax, there are 3 simple things to know:

1 – Objects store details about a particular “thing”, e.g. the $post object will store details like the date and author of the post.

2 – To access a value, you use the following syntax:

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$object->property

e.g. If we wanted to print out the post’s ID, we’d write:

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echo $post->ID;

3 – If you need to see everything that’s in your object, use the following to get a nicely laid out view of it:

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<pre>
<?php print_r($object); ?>
</pr>

(Add in the extra ‘e’ in </pre>. I’ve just taken it out so my syntax highlighter plugin still works!)

The $post Object

Let’s start with the one you will use the most. In every WordPress loop, a global $post variable is set containing everything about that post/page.

This is a global variable, so you can access it outside of the loop. To do that, add this to your PHP before you use it:

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global $post;
Property Value Example
ID Unique post ID. 443
post_author User ID of the author. 1
post_date In the format: yyyy-mm-dd hh:mm:ss 2010-07-29 16:59:54
post_date_gmt Same as above, but in GMT timezone. 2010-07-29 18:59:54
post_content Similar to HTML view in editor. No paragraphs/linebreaks.
post_title Human-readable post title. Your Post Title
post_excerpt Content of the excerpt, if one has been explicitly set.
post_status published/pending/draft published
comment_status open/closed open
ping_status open/closed open
post_password Plain-text version of the posts’ password. password1
post_name The post’s slug. your-post-title
to_ping Addresses entered in the “Send Trackbacks to:” box before publishing. http://problogdesign.com
pinged Addresses entered in the “Send Trackbacks to:” box that have been pinged. http://pliablepress.com
post_modified Server time the post was last modified. 2011-02-01 20:30:08
post_modified_gmt GMT time the post was last modified. 2011-02-01 21:30:08
post_content_filtered “can be used by plugins for caching expensive post content
transformations” (Link)
post_parent ID of the page’s parent (if it has one) 332
guid Unique link to the post (Not the permalink though!) http://problogdesign.com/?p=6335
menu_order Value set in the “Menu Order” box on Pages. 0
post_type post/page/attachment/revision/nav_menu_item/custom-type attachment
post_mime_type MIME type of attachments. image/jpeg
comment_count Number of comments. 7
ancestors Array of parent/grandparent etc. pages. [0] = parent ID [1] = parent’s parent etc. 
Array
 (
       [0] => 61
       [1] => 57
 )
filter How the post content has been filtered before being returned (Default ‘raw’ = minimal filtering/sanitization). raw

For simplicity sake, I’ve referred to certain values as being used for Pages only. Of course, if you’ve defined a custom post type that uses those attributes (e.g. post_parent), then it will be used there too.

Tag and Category Objects

Each individual category or tag can be represented as an object. We’ll start with a quick look at the 3 main functions for getting tag and category objects.

The get_term_by() function is fantastic for finding a single tag or category. You can tell it to search by name, ID, or slug, and whether it’s a tag (post_tag), category or custom taxonomy you’re after, e.g.

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$term = get_term_by('slug', 'featured', 'post_tag');

To get all the tags on a post, you would use the get_the_tags() function, e.g.

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$tags = get_the_tags();
foreach($tags as $term) {
    echo "$term->name | "; 
}

And similarly, to get all of the categories on a post, we’ll use get_the_category():

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$tags = get_the_category();
foreach($tags as $term) {
    echo "$term->name | "; 
}
Property Value Example
term_id The category or tag ID. 42
name The human-readable name. Breaking News
slug Permalink slug for the term. breaking-news
term_group If one term is an alias for another, then both will share the same term group (Default = 0, for all terms) 4
term_taxonomy_id ID of the taxonomy’s entry in the wp_term_taxonomy table. 54
taxonomy category/post_tag post_tag
description Text entered to describe this tag/category. Up-to-the-minute news releases!
parent ID of this term’s parent term (e.g. parent category). 0 if it has none. 0
count Number of posts using this tag/category. 15
object_id ID of the object that the category/tag is attached to, e.g. the post ID 226

For backwards compatibility, the $category object returned stores many of these values under other names as well, e.g. term_id and cat_ID both return the category ID.

To make things easier on yourself though, forget the category-specific versions and use the ones above instead. That way, you won’t have to remember the difference between the tag and category versions.

The $comment Object

Last of all, we’re going to look at the $comment object. During your comments loop, you can access this object to get specific information about the comment.

Property Value Example
comment_ID Unique ID of this comment. 735
comment_post_ID ID of the post this comment was made on. 146
comment_author Name of the commenter. Michael Martin
comment_author_email Commenter’s email address. email@example.com
comment_author_url Commenter’s website address (If they left one) http://problogdesign.com/
comment_author_IP IP address of the commenter. 192.168.0.1
comment_date (Server) Time the comment was left, in format yyyy-mm-dd hh:mm:ss 2011-01-15 14:01:48
comment_date_gmt GMT time that the comment was left. 2011-01-15 16:01:48
comment_content Unfiltered version of the comment’s text (No paragraphs etc.).
comment_karma Unused, and may be removed in future. 0
comment_approved 1 or 0, depending on whether or not the comment is approved. 1
comment_agent Long string of the commenter’s user-agent. Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6… etc.
comment_type Blank for regular comments. Alternatively can be pingback or trackback.
comment_parent If threaded commenting is enabled, the ID of the comment this was in reply to (0 if none). 463
user_id If the comment was made by a logged-in user, then their user ID is stored. 1

And that finishes up our look at the main WordPress objects. There are functions for getting directly at a lot of this information, but at times, it’s far easier to simply take what you need from these objects without worrying about all the different function names.

If you’d like to see examples of how these can be put to use, let me know in the comments and I’ll share some of the ways I’ve used them! And of course, feel free to share your own!

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