Add User ID Column to Users List in WordPress

if ( ! function_exists( 'wpcodebook_add_user_id_column' ) ) {
    /**
     * Adds "ID" column to the "Users" page.
     */
    function wpcodebook_add_user_id_column( $columns ) {
        $columns['user_id'] = __( 'ID', 'text-domain' );
        return $columns;
    }
    add_filter( 'manage_users_columns', 'wpcodebook_add_user_id_column' );
}

if ( ! function_exists( 'wpcodebook_render_user_id_column' ) ) {
    /**
     * Renders "ID" column.
     */
    function wpcodebook_render_user_id_column( $output, $column_name, $user_id ) {
        return ( 'user_id' === $column_name ? $user_id : $output );
    }
    add_filter( 'manage_users_custom_column', 'wpcodebook_render_user_id_column', 10, 3 );
}

Get the min or max variation ID in WooCommerce

if ( ! function_exists( 'wpcodebook_get_variation_id' ) ) {
    /**
     * Get the min or max (by price) active variation ID in WooCommerce.
     */
    function wpcodebook_get_variation_id( $variable_product_id, $min_or_max = 'min' ) {
        $product = wc_get_product( $variable_product_id );
        if ( $product && $product->is_type( 'variable' ) ) {
            $prices        = $product->get_variation_prices( true );
            $variation_ids = array_keys( $prices['price'] );
            return ( 'min' === $min_or_max ? $variation_ids[0] : $variation_ids[ count( $variation_ids ) - 1 ] );
        }
        return false; // not a (variable) product
    }
}

Add "Read more" to Product Short Description in WooCommerce

add_filter( 'woocommerce_short_description', 'wpcb_add_read_more_to_short_description' );
if ( ! function_exists( 'wpcb_add_read_more_to_short_description' ) ) {
    /**
     * wpcb_add_read_more_to_short_description.
     */
    function wpcb_add_read_more_to_short_description( $short_description ) {
        $words     = explode( ' ', $short_description );
        $num_words = 55;
        return ( sizeof( $words ) > $num_words ?
            implode( ' ', array_slice( $words, 0, $num_words ) ) .
                '<details><summary>Read more...</summary>' .
                    implode( ' ', array_slice( $words, $num_words, sizeof( $words ) ) ) . '</details>' :
            $short_description );
    }
}