10.5. List MembershipΒΆ

in and not in are boolean operators that test membership in a sequence. We used them previously with strings and they also work here.

Check your understanding

    list-5-1: What is printed by the following statements?

    alist = [3, 67, "cat", [56, 57, "dog"], [ ], 3.14, False]
    print(3.14 in alist)
    
  • True
  • Yes, 3.14 is an item in the list alist.
  • False
  • There are 7 items in the list, 3.14 is one of them.

    list-5-2: What is printed by the following statements?

    alist = [3, 67, "cat", [56, 57, "dog"], [ ], 3.14, False]
    print(57 in alist)
    
  • True
  • in returns True for top level items only. 57 is in a sublist.
  • False
  • Yes, 57 is not a top level item in alist. It is in a sublist.
Next Section - 10.6. Concatenation and Repetition