loop_shop_columns │ filter-hook │ WC 1.0

Usage

add_filter( 'loop_shop_columns', 'wp_kama_loop_shop_columns_filter' );

/**
 * Function for `loop_shop_columns` filter-hook.
 * 
 * @param  $columns 
 *
 * @return 
 */
function wp_kama_loop_shop_columns_filter( $columns ){

	// filter...
	return $columns;
}

$columns

-

Where the hook is called

$columns = apply_filters( 'loop_shop_columns', $columns );

Where the hook is used in WooCommerce