使用此代码，您将在注册期间检查用户的电子邮件，并附加您想要的角色：

<?php
add_action( \'user_register\', \'wp234_set_role_by_email\' );
function wp234_set_role_by_email( $user_id ){
    $user = get_user_by( \'id\', $user_id );
    $domain = substr(
        strrchr(
            $user->data->user_email, 
            "@"
        ), 1
    ); //Get Domain

    $contributor_domains = array( \'gmail.com\' );
    if( in_array( $domain, $contributor_domains ) ){
        foreach( $user->roles as $role )
            $user->remove_role( $role ); //Remove existing Roles
        $user->add_role( \'contributor\' ); //Add role
    }

    $subscriber_domains = array( \'hotmail.com\' );
    if( in_array( $domain, $subscriber_domains ) ){
        foreach( $user->roles as $role )
            $user->remove_role( $role ); //Remove existing Roles
        $user->add_role( \'subscriber\' ); //Add role
    }

}
?>

<?php
    if( ! in_array( $domain, $contributor_domains ) ){
        foreach( $user->roles as $role )
            $user->remove_role( $role ); //Remove existing Roles
        $user->add_role( \'subscriber\' ); //Add role
    }
?>