# Contributing Hi. 👋🏽 👋 Thank you so much for your interest in contributing to the Python track! **We are happy you are here.** 🌟 🎉 `exercsim/Python` is one of the many tracks on [exercism][exercism-website]. This repo holds all the instructions, tests, code, & support files for Python *exercises* currently under development or implemented & available for students. Exercises are grouped into **concept** exercises which teach the [Python syllabus][python-syllabus], and **practice** exercises, which are unlocked by progressing in the syllabus tree. Practice exercises are open-ended, and can be used to practice concepts learned, try out new techniques, and _play_. These two exercise groupings can be found in the track [config.json][config-json], and under the `python/exercises` directory.
## 🐛 **Did you find a bug?** It's not uncommon that people discover typos, confusing directions, or incorrect implementations of certain tests or code examples. Or you might have a great suggestion for a hint to aid students (💙 ) , see optimizations for exemplar or test code, find some missing test cases to add, or want to correct factual and/or logical errors. Or maybe you have a great idea for an exercise or feature. _Our track is always a work in progress!_ 🌟🌟 Please 📛 [Open an issue][open-an-issue] 📛 , and let us know what you've found.
## 🚧 **Did you write a patch that fixes a bug?** 💛 💙 **We Warmly Welcome Pull Requests that are:** 1️⃣ Small, contained fixes for typos/grammar/punctuation/code syntax on [one] exercise, 2️⃣ Medium changes that have been agreed/discussed via a filed issue, 3️⃣ Contributions from our [help wanted][help-wanted] issue list, 4️⃣ Larger (_and previously agreed-upon_) contributions from recent & regular (_within the last 6 months_) contributors. When in doubt, 📛 [Open an issue][open-an-issue] 📛. We will happily discuss your proposed change. 🐍 But let's talk before you take a whole lot of time implementing anything.
## :books: **Want to jump directly into Exercism specifications & detail?** ✨ 🦄 Here is the good stuff: [Track Structure][exercism-track-structure] **|** [Tasks][exercism-tasks] **|** [Concepts][exercism-concepts] **|** [Concept Exercises][concept-exercises] **|** [Practice Exercises][practice-exercises] **|** [Presentation][exercise-presentation] **|** [ Style Guide for Writing][exercism-writing-style] **|** [Markdown Specification][exercism-markdown-specification] Web-formatted 🕸️ versions are available in the [contributing section][website-contributing-section] of exercsim.org.
## 🌍 The Exercism Community 🌏
🌟🌟 If you have not already done so, please take a moment to read our [Code of Conduct][exercism-code-of-conduct] & [Being a Good Community Member][being-a-good-community-member]. It might also be helpful to take a look at [The words that we use][the-words-that-we-use]. Some defined roles in our community: [Community Member][being-a-good-community-member] **|** [Contributors][exercism-contributors] **|** [Mentors][exercism-mentors] **|** [Maintainers][exercism-track-maintainers] **|** [Admins][exercism-admins]
## In General
- Maintainers are happy to review your work and help you out. 💛 💙 But they may be in a different timezone, or tied up 🧶 with other tasks. **Please wait at least 72 hours before pinging them.** They will review your request as soon as they are able to. - If you'd like in-progress feedback or discussion, please mark your Pull Request as a `[draft]` - Pull requests should be focused on a single exercise, issue, or change. - Pull Request titles and descriptions should make clear **what** has changed and **why**. Please link 🔗 to any related issues the PR addresses. - 📛 [An issue should be opened][open-an-issue] 📛 _**before**_ creating a Pull Request making significant or breaking changes to an existing exercise. - The same holds true for changes across multiple exercises. - It is best to discuss changes with 🧰 maintainers before doing a lot of work. - Follow coding standards found in [PEP8][PEP8] ( ["For Humans" version here][pep8-for-humans]. We do have some more specific requirements. More on that a little later. - All files should have a proper [EOL][EOL] at the end. This means one carriage return at the end of the final line of text in files. - Otherwise, watch out ⚠️ for trailing spaces, extra blank lines, extra spaces, and spaces in blank lines. - The CI is going to run **a lot** of checks on your PR. Pay attention to the failures, try to understand and fix them. If you need help, comment in the PR or issue. 🙋🏽‍♀️ The maintainers are happy to help troubleshoot. ⚠️ **Before committing** ⚠️ - Run `configlet fmt` and `configlet lint` before committing if [config.json](config-json) has been modified. - Run [flake8][flake8] to ensure all Python code conforms to general style standards. - Run `test/check-exercises.py [EXERCISE]` to check if your test changes function correctly. - If you modified or created a `hints.md` file, [regenerate the README](#generating-exercise-readmes)
## A Little More on Prose Writing Style and Standards
Non-code content (_exercise introductions & instructions, hints, concept write-ups, documentation etc._) should be written in [American English][american-english]. We strive to watch [the words we use][the-words-we-use]. When a word or phrase usage is contested | ambiguous, we default to what is best understood by our international community of learners, even if it "sounds a little weird" to a "native" American English speaker. Our documents use [Markdown][markdown-language], with certain [alterations][exercism-markdown-widgets] & [additions][exercism-internal-linking]. Here is our full [Markdown Specification][exercism-markdown-specification]. We format/lint our Markdown with [Prettier][prettier].
## A Little More on Exercises
- Each exercise must be self-contained. Please do not use or reference files that reside outside the given exercise directory. "Outside" files will not be included if a student fetches the exercise via the CLI. - Each exercise/problem should include a complete test suite, an example/exemplar solution, and a stub file ready for student implementation. - See [Concept Exercise Anatomy][concept-exercise-anatomy], or [Practice Exercise Anatomy][practice-exercise-anatomy] depending on which type of exercise you are contributing to. - For **practice exercise**, descriptions and instructions come from a centralized, cross-track [problem specifications][problem-specifications] repository. - Any updates or changes need to be proposed/approved in `problem-specifications` first. - If Python-specific changes become necessary, they need to be appended to the canonical instructions by creating a `instructions.append.md` file in this (`exercism/Python`) repository. - **Practice Exericse Test Suits** for many practice exercises are similarly [auto-generated][##Auto-Generated Test Files and Test Templates] from data in [problem specifications][problem-specifications]. - Any changes to them need to be proposed/discussed in the `problem-specifications` repository and approved by **3 track maintainers**, since changes could potentially affect many (_or all_) exercism language tracks. - If Python-specific test changes become necessary, they can be appended to the exercise `tests.toml` file. 📛 [**Please file an issue**][open-an-issue] 📛 and check with maintainers before adding any Python-specific tests.
## Python Coding Standards

## Python Versions
Exercises on this track officially support Python >= `3.8` Track tooling (`test runners`, `analyzers`, and r`epresenters`) all run on Python `3.9`. * All exercises going forward should be written for compatibility with Python >= `3.8`,. * Version backward _incompatibility_ (*e.g* an exercise using a `3.8` or `3.9` only feature) should be clearly notied in any exercise introduction or notes. * _Most_ exercises will work with Python 3.6+, and _many_ are compatible with Python 2.7+. Please do not change existing exercises to add new `3.6`+ features without consulting with a maintainer first. - All test suites and example solutions must work in all Python versions that we currently support. When in doubt about a feature, please check with maintainers.
## External Libraries and Dependencies

## Auto-Generated Test Files and Test Templates
Practice exericses inherit their definitions from the [problem-specifications][problem-specifications] repository in the form of _description files_. Exercise introductions, instructions and (_in the case of **many**, but not **all**_) test files are machine-generated . Changes to practice exercise _specifications_ should be raised/PR'd in [problem-specifications][problem-specifications] and approved by **3 track maintainers**. After an exercise change has gone through that process , related documents and tests for the Python track will need to be re-generated via [configlet][configlet]. Configlet is also used as part of the track CI, essential track and exercise linting, and other verification tasks. If a practice exercise has an auto-generated `_test.py` file, there will be a `.meta/template.j2` and a `.meta/tests.toml` file in the exercise directory. If an exercise implements Python track-specific tests, there may be a `.meta/additional_tests.json` to define them. These `additional_tests.json` files will automatically be included in test generation. Practice exercise `_test.py` files are generated/regenerated via the [Python Track Test Generator][python-track-test-generator]. Please reach out to a maintainer if you need any help with the process.
## Tools and Tooling ################################## >>>>>>> Formatting Update ## Architecture Exercism tracks inherit exercise definitions from the [problem-specifications] repository in the form of description files (from which exercise READMEs are [generated](#generating-exercise-readmes)) ## Implementing an exercise ### Exercise structure ```Bash exercises/[EXERCISE]/ ├── [EXERCISE].py ├── [EXERCISE]_test.py ├── example.py ├── .meta │ ├── template.j2 │ ├── additional_tests.json │ └── hints.md └── README.md ``` Files: | File | Description | Source | |:--- |:--- |:--- | | [[EXERCISE].py](exercises/two-fer/two_fer.py) | Solution stub | Manually created by the implementer | | [[EXERCISE]_test.py](exercises/two-fer/two_fer_test.py) | Exercise test suite | Automatically generated if `.meta/template.j2` is present, otherwise manually created by the implementer | | [example.py](exercises/two-fer/example.py) | Example solution used to automatically verify the `[EXERCISE]_test.py` suite | Manually created by the implementer | | [.meta/template.j2](exercises/two-fer/.meta/template.j2) | Test generation template; if present used to automatically generate `[EXERCISE]_test.py` (See [generator documentation](docs/GENERATOR.md)) | Manually created by implementer | | [.meta/additional_tests.json](exercises/word-count/.meta/additional_tests.json) | Defines additional track-specific test cases; if `.meta/template.j2` is also present these test will be incorporated into the automatically generated `[EXERCISE]_test.py` | Manually created by the implementer | | [.meta/hints.md](exercises/high-scores/.meta/hints.md) | Contains track-specific hints that are automatically included in the generated `README.md` file | Manually created by the implementer | | [README.md](exercises/two-fer/README.md) | Exercise README | [Generated by `configlet` tool](#generating-exercise-readmes) | ### Generating Exercise READMEs #### Requirements - A local clone of the [problem-specifications] repository. - [configlet]: may be obtained either by - (**Recommended**) Following installation instructions at the above link - Running `bin/fetch-configlet` (`configlet` binary will be downloaded to the repository `bin/`) #### Generating all READMEs ``` configlet generate --spec-path path/to/problem/specifications ``` #### Generating a single README ``` configlet generate --spec-path path/to/problem/specifications --only example-exercise ``` ### Implementing tests If an unimplemented exercise has a `canonical-data.json` file in the [problem-specifications] repository, a generation template must be created. See the [test generator documentation](docs/GENERATOR.md) for more information. If an unimplemented exercise does not have a `canonical-data.json` file, the test file must be written manually (use existing test files for examples). ### Example solutions Example solution files serve two purposes: 1. Verification of the tests 2. Example implementation for mentor/student reference ### config.json [`config.json`](config.json) is used by the website to determine which exercises to load an in what order. It also contains some exercise metadata, such as difficulty, labels, and if the exercise is a core exercise. New entries should be places just before the first exercise that is marked `"deprecated": true`: ```JSON { "slug": "current-exercise", "uuid": "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa", "core": false, "unlocked_by": null, "difficulty": 1, "topics": [ "strings" ] }, <<< HERE { "slug": "old-exercise", "uuid": "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa", "core": false, "unlocked_by": null, "difficulty": 2, "topics": null, "status": "deprecated" }, ``` Fields

slug	Hyphenated lowercase exercise name
uuid	Generate using `configlet uuid`
core	Set to `false`; core exercises are decided by track maintainers
unlocked_by	Slug for the core exercise that unlocks the new one
difficulty	`1` through `10`. Discuss with reviewer if uncertain.
topics	Array of relevant topics from the topics list

## Implementing Track-specific Exercises Similar to implementing a canonical exercise that has no `canonical-data.json`, but the exercise README will also need to be written manually. Carefully follow the structure of generated exercise READMEs. [EOL]: https://en.wikipedia.org/wiki/Newline [PEP8]: https://www.python.org/dev/peps/pep-0008/ [american-english]: https://github.com/exercism/docs/blob/main/building/markdown/style-guide.md [being-a-good-community-member]: https://github.com/exercism/docs/tree/main/community/good-member [concept-exercise-anatomy]: https://github.com/exercism/docs/blob/main/building/tracks/concept-exercises.md [concept-exercises]: https://github.com/exercism/docs/blob/main/building/tracks/concept-exercises.md [config-json]: https://github.com/exercism/javascript/blob/main/config.json [configlet-general]: https://github.com/exercism/configlet [configlet]: https://github.com/exercism/docs/blob/main/building/configlet/generating-documents.md [exercise-presentation]: https://github.com/exercism/docs/blob/main/building/tracks/presentation.md [exercism-admins]: https://github.com/exercism/docs/blob/main/community/administrators.md [exercism-code-of-conduct]: https://exercism.org/docs/using/legal/code-of-conduct [exercism-concepts]: https://github.com/exercism/docs/blob/main/building/tracks/concepts.md [exercism-contributors]: https://github.com/exercism/docs/blob/main/community/contributors.md [exercism-internal-linking]: https://github.com/exercism/docs/blob/main/building/markdown/internal-linking.md [exercism-markdown-specification]: https://github.com/exercism/docs/blob/main/building/markdown/markdown.md [exercism-markdown-widgets]: https://github.com/exercism/docs/blob/main/building/markdown/widgets.md [exercism-mentors]: https://github.com/exercism/docs/tree/main/mentoring [exercism-tasks]: https://exercism.org/docs/building/product/tasks [exercism-track-maintainers]: https://github.com/exercism/docs/blob/main/community/maintainers.md [exercism-track-structure]: https://github.com/exercism/docs/tree/main/building/tracks [exercism-website]: https://exercism.org/ [exercism-writing-style]: https://github.com/exercism/docs/blob/main/building/markdown/style-guide.md [flake8]: http://flake8.pycqa.org/ [help-wanted]: https://github.com/exercism/python/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22 [markdown-language]: https://guides.github.com/pdfs/markdown-cheatsheet-online.pdf [open-an-issue]: https://github.com/exercism/python/issues/new/choose [pep8-for-humans]: https://pep8.org/ [practice-exercise-anatomy]: https://github.com/exercism/docs/blob/main/building/tracks/practice-exercises.md [practice-exercises]: https://github.com/exercism/docs/blob/main/building/tracks/practice-exercises.md [prettier]: https://prettier.io/ [problem-specifications]: https://github.com/exercism/problem-specifications [python-syllabus]: https://exercism.org/tracks/python/concepts [python-track-test-generator]: https://github.com/exercism/python/blob/main/docs/GENERATOR.md [the-words-that-we-use]: https://github.com/exercism/docs/blob/main/community/good-member/words.md [website-contributing-section]: https://exercism.org/docs/building