Track 6 · Lesson 11 of 12

Copying and aliasing: when two names share one list

Understand that assignment shares objects, tell == from is, and choose between shallow and deep copies to avoid mutation bugs.

You will be able to

• Explain that assignment makes a second name for the same object, not a copy
• Tell the difference between == (same value) and is (same object)
• Make shallow copies with list(), .copy() and slicing, and deep copies with copy.deepcopy()
• Find and fix bugs caused by shared mutable data, including mutable default arguments