Test your knowledge: Python Tuples and Sets

Review

1. Which expression creates a one-item tuple?

   A singleton tuple needs the trailing comma: ("Python",). Parentheses alone only group an expression.
2. What happens when code tries to assign to an existing tuple element?

   Tuple elements cannot be assigned after the tuple is created, so item assignment raises TypeError.
3. What does {"Python", "Python", "CSS"} contain?

   A set keeps one occurrence of each distinct element, so the duplicate Python value does not add another element.
4. What does a & b produce for two sets?

   Intersection keeps the elements that belong to both sets.
5. Why can a frozenset be used as a set element?

   frozenset is immutable and hashable, so a frozenset can itself be an element of a set or a dictionary key.