username_exists() – Function | Developer.WordPress.org

Determines whether the given username exists.

Description

For more information on this and similar theme functions, check out the Conditional Tags article in the Theme Developer Handbook.

Parameters

$usernamestringrequired: The username to check for existence.

Return

int|false The user ID on success, false on failure.

Source

function username_exists( $username ) {
	$user = get_user_by( 'login', $username );
	if ( $user ) {
		$user_id = $user->ID;
	} else {
		$user_id = false;
	}

	/**
	 * Filters whether the given username exists.
	 *
	 * @since 4.9.0
	 *
	 * @param int|false $user_id  The user ID associated with the username,
	 *                            or false if the username does not exist.
	 * @param string    $username The username to check for existence.
	 */
	return apply_filters( 'username_exists', $user_id, $username );
}

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Hooks

apply_filters( ‘username_exists’, int|false $user_id, string $username ): Filters whether the given username exists.

Uses	Description
get_user_by()`wp-includes/pluggable.php`	Retrieves user info by a given field.
apply_filters()`wp-includes/plugin.php`	Calls the callback functions that have been added to a filter hook.

Used by	Description
wp_install()`wp-admin/includes/upgrade.php`	Installs the site.
edit_user()`wp-admin/includes/user.php`	Edit user settings based on contents of $_POST
WP_Importer::set_user()`wp-admin/includes/class-wp-importer.php`
register_new_user()`wp-includes/user.php`	Handles registering a new user.
wp_insert_user()`wp-includes/user.php`	Inserts a user into the database.
wpmu_activate_signup()`wp-includes/ms-functions.php`	Activates a signup.
wpmu_validate_user_signup()`wp-includes/ms-functions.php`	Sanitizes and validates data required for a user sign-up.
wpmu_validate_blog_signup()`wp-includes/ms-functions.php`	Processes new site registrations.

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Changelog

Version	Description
2.0.0	Introduced.

User Contributed Notes

Skip to note 3 content

Codex 9 years ago

You must log in to vote on the helpfulness of this noteVote results for this note: -1You must log in to vote on the helpfulness of this note
Example
Use username_exists() in your scripts to decide whether the given username exists.
```
$username = sanitize_user( $_POST['username'] );
if ( username_exists( $username ) ) {
	echo "Username In Use!";
} else {
	echo "Username Not In Use!";
}
```
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Skip to note 4 content

nasimnet 4 years ago

You must log in to vote on the helpfulness of this noteVote results for this note: -1You must log in to vote on the helpfulness of this note
Example
This function first checks username exist and if not exist, create user.
```
function wpdocs_get_user_id( $username ) {
	$user_id = username_exists( $username );

	if ( ! $user_id ) {
		$userdata = array(
			'user_login' => $username,
			'user_pass'  => null,
		);

		$user_id = wp_insert_user( $userdata );
	}

	return $user_id;
}
```
- wp_insert_user() checks if the username exists (by using username_exists()), so this would be redundant (and potentially costly).
  
  crstauf 4 years ago
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username_exists( string $username ): int|false

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