Copy post from category to custum post type

Question

Create your custom post type and then try this. (BACKUP FIRST AS THIS IS UNTESTED).

<?php

// Get all posts in category "5"
$news_posts = get_posts(
    array(
        'category'  =>  5
    )
);

// Loop through them
foreach($news_posts as $p):

    // Update the post type
    wp_update_post(
        array(
            'ID'        =>  $p->ID,
            'post_type' =>  'news'
        );
    );

    // Delete term relationships for the post
    wp_delete_object_term_relationships( $p->ID, 'post_tag' );
    wp_delete_object_term_relationships( $p->ID, 'category' );  

endforeach;

?>