Misconception: Students think you can use the “item (any) of (list)” block in Snap! and Scratch to check for every item in a list, but this block actually returns a random item.

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  • Students often try to write something like the following to check every item in a list:
      • The block above reads: "hello" = item (any) of (list)
    • This will fail most of the time because any is a random item.
  • The contains block is what students should use in order to achieve the task they are trying to complete:
      • (list) contains
      • The block above reads: (list) contains "hello"
    • This block reports whether or not the item exists in the list. If the item if found, it reports TRUE, otherwise it will report FALSE.
  • You can actually make your own version of contains!
    • Here’s one way to create contains in Snap! +is+search for+in+the+list+(list)+ script variables (position) set (position) to 1 repeat (length of (list)) if (search for)=(item(position)of(list)) report true else change (position) by 1 report false

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External Source
Michael Ball and Lauren Mock at the CS NYC Tip-A-Thon
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Lauren Mock