Getting to know all WordPress functions


Getting to know all WordPress functions

Functions on WordPress

On WordPress, the functions are placed in the functions.php file, and you can change the functions in this file or put custom code in it.

The functions.php file is automatically loaded when you install and activate a WordPress theme, and we've included all the functions here.

This file acts like a WordPress plugin for your WordPress site and is automatically activated with your current theme. The functions.php file uses PHP code to add features or change default features on the site.

For example, a WordPress theme might add a bit of code to the functions.php file to add a new widget area to the footer, or add a custom welcome message to the WordPress dashboard.

Editing the functions.php file with custom code allows you to add post types, categories, short codes, and more to improve your website.

In any case, with the help of this file, you can add endless features to the website without installing a plugin.

Where is the location of the WordPress functions file?

The location of the functions.php file is in the template folder. If you want to add a piece of code to a WordPress site, adding it to the functions.php file is one option. But this is usually not the best way to do it. WordPress tries to separate design and functionality as much as possible. That's why we have themes that define design and plugins that define functionality.

It's even better if you can change your WordPress theme without changing how your site works, or change your plugins without affecting your site design.

If you decide to edit this file, please be very careful or preferably get help from an expert. In the following, we have given 3 important reasons to be careful when editing the functions.php file.

3 important reasons to be cautious when editing the functions.php file

Editing this file should be done carefully. 3 reasons for the importance of this issue are:

  1. Editing functions on WordPress will be lost when the theme is updated.
  2. If you change your WordPress theme, the edits will be lost.
  3. Creating coding errors in the functions file can damage the site.

Even something as simple as an extra semicolon can cause your entire site to fail. So if you need to change this file, get help from experienced people.

Coding mistakes in the functions.php file can also lead to various WordPress errors. You only need to edit a functions.php file if you have a child theme, and code snippets are only used with the active child theme. For example, you might want to add snippets for custom fonts, style sheets, or a language translation file specifically for a theme.

Introduction of all WordPress functions

WordPress files define many useful PHP functions. Some functions on WordPress, known as template tags, are specifically defined for use in WordPress themes. There are also some functions related to actions and filters (Plugin API), which are mainly used for developing plugins. The rest is used to create the core functionality of WordPress.

Many core WordPress functions are useful for plugin and theme developers. So, here we list most of the main functions, excluding the template tags.

All these functions are basic and necessary, and knowing them is essential for people who want to make changes to your WordPress codes.

Post functions

  • get_adjacent_post
  • get_boundary_post
  • get_children
  • get_extended
  • get_next_post
  • get_next_posts_link
  • next_posts_link
  • get_permalink
  • the_permalink
  • get_the_excerpt
  • the_excerpt
  • get_the_post_thumbnail
  • get_post
  • get_post_field
  • get_post_ancestors
  • get_post_mime_type
  • get_post_status
  • get_post_format
  • set_post_format
  • get_edit_post_link
  • get_delete_post_link
  • get_previous_post
  • get_previous_posts_link
  • previous_posts_link
  • get_posts
  • have_posts
  • is_post
  • is_single
  • is_sticky
  • get_the_ID
  • the_ID
  • the_post
  • wp_get_recent_posts
  • wp_get_single_post
  • has_post_thumbnail
  • has_excerpt
  • has_post_format

Custom post functions

  • register_post_status

Custom post type

  • register_post_type
  • is_post_type_archive
  • post_type_archive_title
  • add_post_type_support
  • remove_post_type_support
  • post_type_supports
  • set_post_type
  • post_type_exists
  • get_post_type
  • get_post_types
  • get_post_type_archive_link
  • get_post_type_object
  • get_post_type_capabilities
  • get_post_type_labels
  • is_post_type_hierarchical

Post insertion and deletion

  • wp_delete_post
  • wp_insert_post
  • wp_publish_post
  • wp_trash_post
  • wp_update_post

pages

  • get_all_page_ids
  • get_ancestors
  • get_page
  • get_page_link
  • get_page_by_path
  • get_page_by_title
  • get_page_children
  • get_page_hierarchy
  • get_page_uri
  • get_pages
  • is_page
  • page_uri_index
  • wp_link_pages
  • wp_list_pages
  • wp_page_menu
  • wp_dropdown_pages

Custom fields (postmeta)

  • add_post_meta
  • delete_post_meta
  • get_post_custom
  • get_post_custom_keys
  • get_post_custom_values
  • get_post_meta
  • update_post_meta
  • register_meta

attachments

  • get_attached_file
  • image_resize
  • image_edit_before_change
  • is_attachment
  • is_local_attachment
  • set_post_thumbnail
  • update_attached_file
  • wp_attachment_is_image
  • wp_create_thumbnail
  • wp_insert_attachment
  • wp_delete_attachment
  • wp_get_attachment_image
  • wp_get_attachment_link
  • wp_get_attachment_image_src
  • wp_get_attachment_metadata
  • wp_get_attachment_thumb_file
  • wp_get_attachment_thumb_url
  • wp_get_attachment_url
  • wp_check_for_changed_slugs
  • wp_count_posts
  • wp_get_mime_types
  • wp_mime_type_icon
  • wp_generate_attachment_metadata
  • wp_prepare_attachment_for_js
  • wp_update_attachment_metadata

Bookmark

  • get_bookmark
  • get_bookmarks
  • wp_list_bookmarks

Main items

  • wp_get_post_categories
  • wp_set_post_categories
  • wp_get_post_tags
  • wp_set_post_tags
  • wp_get_post_terms
  • wp_set_post_terms
  • wp_count_terms
  • has_term
  • is_object_in_term

Other cases

  • add_meta_box
  • remove_meta_box
  • get_the_ID
  • the_ID
  • get_the_author
  • the_author
  • get_the_author_posts
  • get_the_content
  • the_content
  • get_the_title
  • the_title
  • the_title_attribute
  • wp_trim_excerpt
  • wp_get_post_revision
  • wp_get_post_revisions
  • wp_is_post_revision
  • paginate_links

Categories

  • cat_is_ancestor_of
  • get_all_category_ids
  • get_ancestors
  • get_cat_ID
  • get_cat_name
  • get_categories
  • get_category
  • get_category_by_path
  • get_category_by_slug
  • get_the_category_by_ID
  • get_the_category_list
  • get_category_link
  • get_category_parents
  • get_the_category
  • single_cat_title
  • in_category
  • is_category
  • the_category
  • wp_category_checklist
  • wp_dropdown_categories
  • wp_list_categories

Create category

  • wp_create_category
  • wp_delete_category
  • wp_insert_category

tags

  • get_tag
  • get_tag_link
  • get_tags
  • get_the_tag_list
  • get_the_tags
  • has_tag
  • is_tag
  • the_tags
  • single_tag_title
  • tag_description
  • wp_generate_tag_cloud
  • wp_tag_cloud

Grouping

  • get_object_taxonomies
  • get_edit_term_link
  • get_taxonomy
  • get_taxonomies
  • get_term
  • get_the_term_list
  • get_term_by
  • the_terms
  • get_the_terms
  • get_term_children
  • get_term_link
  • get_terms
  • is_taxonomy
  • is_tax
  • is_taxonomy_hierarchical
  • is_term
  • taxonomy_exists
  • term_exists
  • register_taxonomy
  • register_taxonomy_for_object_type
  • wp_get_object_terms
  • wp_remove_object_terms
  • wp_set_object_terms
  • wp_insert_term
  • wp_update_term
  • wp_delete_term
  • wp_terms_checklist

The role of management and others

  • add_cap
  • add_role
  • author_can
  • current_user_can
  • current_user_can_for_blog
  • get_role
  • get_super_admins
  • is_super_admin
  • map_meta_cap
  • remove_cap
  • remove_role
  • user_can

Users and authors

  • auth_redirect
  • count_users
  • count_user_posts
  • count_many_users_posts
  • email_exists
  • get_currentuserinfo
  • get_current_user_id
  • get_profile
  • get_user_by
  • get_userdata
  • get_usernumposts
  • get_users
  • set_current_user
  • user_pass_ok
  • wp_authenticate
  • username_exists
  • validate_username
  • wp_dropdown_users
  • wp_get_current_user
  • wp_set_current_user
  • wp_set_password
  • get_author_posts_url
  • get_the_modified_author
  • is_multi_author

User meta

  • add_user_meta
  • delete_user_meta
  • get_user_meta
  • update_user_meta
  • get_the_author_meta

User registration and deletion

  • wp_create_user
  • wp_delete_user
  • wp_insert_user
  • wp_update_user

login / logout

  • is_user_logged_in
  • wp_login_form
  • wp_signon
  • wp_logout
  • wp_loginout
  • wp_logout_url

Feed function

  • bloginfo_rss
  • comment_author_rss
  • comment_link
  • comment_text_rss
  • do_feed
  • do_feed_atom
  • do_feed_rdf
  • do_feed_rss
  • do_feed_rss2
  • fetch_feed
  • fetch_rss
  • get_author_feed_link
  • get_bloginfo_rss
  • get_category_feed_link
  • get_comment_link
  • get_comment_author_rss
  • get_post_comments_feed_link
  • get_rss
  • get_search_comments_feed_link
  • get_search_feed_link
  • get_the_category_rss
  • get_the_title_rss
  • permalink_single_rss
  • post_comments_feed_link
  • rss_enclosure
  • the_title_rss
  • the_category_rss
  • the_content_rss
  • the_excerpt_rss
  • wp_rss

HTTP API functions

  • wp_remote_get
  • wp_remote_retrieve_body
  • wp_get_http_headers
  • wp_remote_fopen

Views, ping and tracking functions

  • add_ping
  • add_comment_meta
  • check_comment
  • comment_text
  • comment_form
  • comments_number
  • discover_pingback_server_uri
  • delete_comment_meta
  • do_all_pings
  • do_enclose
  • do_trackbacks
  • generic_ping
  • get_approved_comments
  • get_avatar
  • get_comment
  • get_comment_text
  • get_comment_meta
  • get_comments
  • wp_list_comments
  • get_enclosed
  • get_lastcommentmodified
  • get_pung
  • get_to_ping
  • have_comments
  • get_comment_author
  • is_trackback
  • pingback
  • privacy_ping_filter
  • sanitize_comment_cookies
  • trackback
  • trackback_url
  • trackback_url_list
  • update_comment_meta
  • weblog_ping
  • wp_allow_comment
  • wp_count_comments
  • wp_delete_comment
  • wp_filter_comment
  • wp_get_comment_status
  • wp_get_current_commenter
  • wp_insert_comment
  • wp_new_comment
  • wp_set_comment_status
  • wp_throttle_comment_flood
  • wp_update_comment
  • wp_update_comment_count
  • wp_update_comment_count_now

Comments functions

  • comment_class
  • comment_ID
  • comment_author
  • comment_date
  • comment_time
  • get_comment_date
  • get_comment_time

Pagination of comments

  • paginate_comments_links
  • previous_comments_link
  • next_comments_link
  • get_comment_pages_count

Functions of filters

  • has_filter
  • add_filter
  • apply_filters
  • apply_filters_ref_array
  • current_filter
  • merge_filters
  • remove_filter
  • remove_all_filters

Functions of actions

  • has_action
  • add_action
  • do_action
  • do_action_ref_array
  • did_action
  • remove_action
  • remove_all_actions

Functions of plugins

  • plugin_basename
  • plugins_url
  • get_plugin_data
  • get_admin_page_title
  • plugin_dir_path
  • register_activation_hook
  • register_deactivation_hook
  • menu_page_url
  • is_plugin_active
  • is_plugin_active_for_network
  • is_plugin_inactive
  • is_plugin_page
  • add_contextual_help
  • get_plugins

Widgets

  • is_active_widget
  • register_widget
  • the_widget
  • unregister_widget
  • wp_add_dashboard_widget
  • wp_convert_widget_settings
  • wp_get_sidebars_widgets
  • wp_get_widget_defaults
  • wp_register_sidebar_widget
  • wp_register_widget_control
  • wp_set_sidebars_widgets
  • wp_unregister_sidebar_widget
  • wp_unregister_widget_control
  • wp_widget_description

Settings

  • register_setting
  • unregister_setting
  • settings_fields
  • do_settings_fields
  • do_settings_sections
  • add_settings_field
  • add_settings_section
  • add_settings_error
  • get_settings_errors
  • settings_errors

Shortcodes

  • add_shortcode
  • do_shortcode
  • do_shortcode_tag
  • get_shortcode_regex
  • remove_shortcode
  • remove_all_shortcodes
  • shortcode_atts
  • shortcode_parse_atts
  • strip_shortcodes

Format related functions

  • comments_template
  • get_footer
  • get_header
  • get_sidebar
  • get_search_form

Other functions

  • add_custom_background
  • add_custom_image_header
  • add_image_size
  • add_theme_support
  • body_class
  • current_theme_supports
  • dynamic_sidebar
  • get_404_template
  • get_archive_template
  • get_attachment_template
  • get_author_template
  • get_body_class
  • get_category_template
  • get_comments_popup_template
  • get_current_theme
  • get_date_template
  • get_header_image
  • get_header_textcolor
  • get_home_template
  • get_locale_stylesheet_uri
  • get_page_template
  • get_paged_template
  • get_post_class
  • get_query_template
  • get_search_template
  • get_single_template
  • get_stylesheet
  • get_stylesheet_directory
  • get_stylesheet_directory_uri
  • get_stylesheet_uri
  • get_tag_template
  • get_taxonomy_template
  • get_template
  • get_template_directory
  • get_template_directory_uri
  • get_theme_file_uri
  • get_theme_file_path
  • get_template_part
  • get_theme
  • wp_get_themes
  • get_theme_data
  • get_theme_support
  • get_theme_mod
  • get_theme_mods
  • get_theme_root
  • get_theme_roots
  • get_theme_root_uri
  • get_themes
  • has_header_image
  • header_image
  • header_textcolor
  • in_the_loop
  • is_child_theme
  • is_active_sidebar
  • is_admin_bar_showing
  • is_customize_preview
  • is_dynamic_sidebar
  • language_attributes
  • load_template
  • locale_stylesheet
  • locate_template
  • post_class
  • preview_theme
  • preview_theme_ob_filter
  • preview_theme_ob_filter_callback
  • register_nav_menu
  • register_nav_menus
  • get_registered_nav_menus
  • wp_create_nav_menu
  • register_sidebar
  • register_sidebars
  • register_theme_directory
  • remove_theme_mod
  • remove_theme_mods
  • remove_theme_support
  • require_if_theme_supports
  • search_theme_directories
  • set_theme_mod
  • switch_theme
  • validate_current_theme
  • unregister_nav_menu
  • unregister_sidebar
  • wp_add_inline_style
  • wp_clean_themes_cache
  • wp_get_archives
  • wp_get_nav_menu_items
  • wp_get_theme
  • wp_nav_menu
  • wp_oembed_remove_provider
  • wp_page_menu
  • wp_title

Formatting functions

  • absint
  • add_magic_quotes
  • addslashes_gpc
  • antispambot
  • attribute_escape
  • backslashit
  • balanceTags
  • clean_pre
  • clean_url
  • convert_chars
  • convert_smilies
  • ent2ncr
  • esc_attr
  • esc_html
  • esc_js
  • esc_textarea
  • esc_sql
  • esc_url
  • esc_url_raw
  • force_balance_tags
  • format_to_edit
  • format_to_post
  • funky_javascript_fix 
  • htmlentities2
  • is_email
  • js_escape 
  • make_clickable
  • popuplinks
  • remove_accents
  • sanitize_email
  • sanitize_file_name
  • sanitize_html_class
  • sanitize_key
  • sanitize_mime_type
  • sanitize_option
  • sanitize_sql_orderby
  • sanitize_text_field
  • sanitize_title
  • sanitize_title_for_query
  • sanitize_title_with_dashes
  • sanitize_user
  • seems_utf8
  • stripslashes_deep
  • trailingslashit
  • untrailingslashit
  • urlencode_deep
  • url_shorten
  • utf8_uri_encode
  • wpautop
  • wptexturize
  • wp_filter_kses
  • wp_filter_post_kses
  • wp_filter_nohtml_kses
  • wp_iso_descrambler
  • wp_kses
  • wp_kses_array_lc
  • wp_kses_attr
  • wp_kses_bad_protocol
  • wp_kses_bad_protocol_once
  • wp_kses_bad_protocol_once2
  • wp_kses_check_attr_val
  • wp_kses_decode_entities
  • wp_kses_hair
  • wp_kses_hook
  • wp_kses_html_error
  • wp_kses_js_entities
  • wp_kses_no_null
  • wp_kses_normalize_entities
  • wp_kses_normalize_entities2
  • wp_kses_post
  • wp_kses_split
  • wp_kses_split2
  • wp_kses_stripslashes
  • wp_kses_version
  • wp_make_link_relative
  • wp_normalize_path
  • wp_rel_nofollow
  • wp_richedit_pre
  • wp_specialchars
  • wp_trim_words
  • zeroise

The importance of functions on WordPress

The importance of functions on WordPress

All WordPress themes come with a powerful functions.php file. This file acts as a plugin and allows you to do many things on your WordPress site. Changes that can create a huge transformation in your site.

Changing these codes requires sufficient knowledge of PHP. If you don't have experience working with them, we suggest you get help from experienced people.

We hope this article from KeyUpSeo blog was useful for you in getting to know the functions of WordPress.


Release date : 13 June, 2024

Categories

SEO

SEO

Google Ads

Google Ads

Digital Marketing

Digital Marketing

Social Media

Social Media

WordPress content and other articles

WordPress content and other articles

Similar contents

Maintaining the security of the WordPress website

Maintaining the security of the WordPress website

WordPress security is a very important issue for any website, and we will teach you the most important things to keep your WordPress website safe

WordPress content and other articles

8 July, 2024

Let's get to know the functions of WordPress better

Let's get to know the functions of WordPress better

The functions.php file is automatically loaded when you install and activate a WordPress theme, and we've included all the functions here.

WordPress content and other articles

13 June, 2024

How to Fix Update Failed Error on WordPress

How to Fix Update Failed Error on WordPress

In this content from the KeyUpSeo blog, you will learn how to fix the failed publication error for WordPress pages with 7 simple methods.

WordPress content and other articles

22 May, 2024