1.5 List

1.5 List

After this unit you will: work with lists without falling into the copying trap.

Key points

• A list is ordered, mutable, and allows duplicates: nums[0] = 99.
• Adding/removing: append, insert, extend, remove, pop, del, clear.
• b = a does not make a copy — both names point to the same list. For a real copy, use a.copy().
• a.sort() sorts in place; sorted(a) returns a new list.