[Python] Implement new Concept Exercise: lists

[aldraco]

This issue describes how to implement the lists concept exercise for the Python track.

Getting started

Please please please read the docs before starting. Posting PRs without reading these docs will be a lot more frustrating for you during the review cycle, and exhaust Exercism's maintainers' time. So, before diving into the implementation, please read up on the following documents:

• The features of v3.
• Rationale for v3.
• What are concept exercise and how they are structured?

Please also watch the following video:

• The Anatomy of a Concept Exercise.

Goal

The goal of this exercise is to teach the basics of the List (sequence type) data type in Python. We will accomplish this by requiring the student to create lists via various methods, iterate through a list via loop, access items in the list at a certain index, and form/access slices of the list.

Learning objectives

• Create a list via constructor (list()) & literal ([])
  • Combine two or more lists by concatenation via +
  • Check for an items membership/absence in a list using in and/or not in
• Access items in a list via index (bracket notation)
• Access a range of items in a list via list slicing ([start:stop:step])
• Iterate through a list using for item in
• Understand that lists can store mixed/any data types
  • Understand that lists are mutable. Assigning a new value to a list index will change the value at that index.

Out of scope

• List Comprehensions (these will be covered in their own concept exercise)
• List methods (copy(), append(), sort() etc)
• How builtin functions relate to lists (len(), max(), min(), count(), sorted())
• Construction of complex or nested lists (i.e a list of dicts, a list of lists, a list of tuples)
• Consequences and considerations of mutability

Concepts

• lists
• indexing
• slicing
• concatenation
• iteration

Prerequisites

• builtin-types
• data-types

Resources to refer to

Python lists doc

Hints

Hints should link to the list instance methods doc page.

After

After, the student can explore the list comprehension pattern, even though it will be taught separately. This is also a good time to reference some builtin methods like len(), or max() - not as a teaching item, but to expose the student to their existence and build familiarity.

Representer

No changes required.

Analyzer

No changes required.

Implementing

Tests should be written using unittest.TestCase, and the test file named lists_basic_test.py.

Help

If you have any questions while implementing the exercise, please post the questions as comments in this issue.

Edits

• edited for updated naming by @yawpitch
• edited to add additional learning objectives by @BethanyG.
• edited to clarify out of scope language by @BethanyG
• edited After section wording. @BethanyG

[BethanyG]

@itamargal will be taking this on. 🌟 😄

[BethanyG]

This was closed by #1583 and #1932