This starter is for exploring the keep block, which takes a predicate and a list and reports a new list of just the items that make the predicate true. It contains an initialize list block that fills the global words list variable (look inside it to see how), and two example keep expressions sitting in the scripting area — one that keeps five-letter words and one that keeps items that are not numbers.

Run the examples and make sure you can explain what each one is doing. Then run initialize list if the words aren't already on the stage, and write your own keep expressions to answer questions about words list — for example, how many 12-, 15-, and 17-letter words it contains.

Your work autosaves (and you can use the Save button); earlier versions are available from the Revisions dropdown.