10.5. List Membership¶

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

fruit = ["apple", "orange", "banana", "cherry"] print("apple" in fruit) print("pear" in fruit)

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)

• (A) True
• Yes, 3.14 is an item in the list alist.
• (B) 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)

• (A) True
• in returns True for top level items only. 57 is in a sublist.
• (B) False
• Yes, 57 is not a top level item in alist. It is in a sublist.