Astute screen-scraper Fred came up with a scenario that arises from time-to-time: you’ve got a page containing one or more HTML tables, all of which are nearly identical in structure. You want to pull the data from each table, but need to be able to distinguish which row came from which table. Standard old extractor patterns won’t do the job–they’ll match every row in every table, which destroys the link between each row and its corresponding table.
Fortunately, there are a couple of ways of handling such a scenario, which I’ve just outlined in this FAQ. Not too complicated, but a bit more involved than just using a standard extractor pattern.