Copying vs Aliasing Python Lists

Assigning one list variable to another can look like a copy, but both names may still lead to the same list. This Block makes that behavior easy to recognize. You will see how shared mutations work, create independent lists with .copy() and [:], and learn why mutation is different from reassignment.

What you will learn:

• Recognize when two variables are aliases for one list
• Predict how appending, replacing, and removing items affect aliases
• Create independent shallow copies with .copy() and [:]
• Choose between an intentionally shared list and a separate editable copy
• Understand mutation, reassignment, and the shallow-copy caveat for nested lists

Leave with a simple rule you can use whenever lists are assigned: share on purpose, or copy before making independent changes.