10.3. List LengthΒΆ

As with strings, the function len returns the length of a list (the number of items in the list). However, since lists can have items which are themselves lists, it important to note that len only returns the top-most length. In other words, sublists are considered to be a single item when counting the length of the list.

Check your understanding

    list-3-1: What is printed by the following statements?

    alist = [3, 67, "cat", 3.14, False]
    print(len(alist))
    
  • 4
  • len returns the actual number of items in the list, not the maximum index value.
  • 5
  • Yes, there are 5 items in this list.

    list-3-2: What is printed by the following statements?

    alist = [3, 67, "cat", [56, 57, "dog"], [ ], 3.14, False]
    print(len(alist))
    
  • 7
  • Yes, there are 7 items in this list even though two of them happen to also be lists.
  • 8
  • len returns the number of top level items in the list. It does not count items in sublists.
Next Section - 10.4. Accessing Elements