diff --git a/rotational-cipher/.exercism/config.json b/rotational-cipher/.exercism/config.json new file mode 100644 index 0000000..d21c3ca --- /dev/null +++ b/rotational-cipher/.exercism/config.json @@ -0,0 +1,30 @@ +{ + "authors": [ + "krapes" + ], + "contributors": [ + "akashsara", + "behrtam", + "cmccandless", + "Dog", + "dotrungkien", + "ikhadykin", + "lekum", + "N-Parsons", + "tqa236" + ], + "files": { + "solution": [ + "rotational_cipher.py" + ], + "test": [ + "rotational_cipher_test.py" + ], + "example": [ + ".meta/example.py" + ] + }, + "blurb": "Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.", + "source": "Wikipedia", + "source_url": "https://en.wikipedia.org/wiki/Caesar_cipher" +} diff --git a/rotational-cipher/.exercism/metadata.json b/rotational-cipher/.exercism/metadata.json new file mode 100644 index 0000000..2162958 --- /dev/null +++ b/rotational-cipher/.exercism/metadata.json @@ -0,0 +1 @@ +{"track":"python","exercise":"rotational-cipher","id":"26e4a0f518d449fa83d98ca4d48f99b9","url":"https://exercism.org/tracks/python/exercises/rotational-cipher","handle":"myFirstCode","is_requester":true,"auto_approve":false} \ No newline at end of file diff --git a/rotational-cipher/HELP.md b/rotational-cipher/HELP.md new file mode 100644 index 0000000..d45cf55 --- /dev/null +++ b/rotational-cipher/HELP.md @@ -0,0 +1,130 @@ +# Help + +## Running the tests + +We use [pytest][pytest: Getting Started Guide] as our website test runner. +You will need to install `pytest` on your development machine if you want to run tests for the Python track locally. +You should also install the following `pytest` plugins: + +- [pytest-cache][pytest-cache] +- [pytest-subtests][pytest-subtests] + +Extended information can be found in our website [Python testing guide][Python track tests page]. + + +### Running Tests + +To run the included tests, navigate to the folder where the exercise is stored using `cd` in your terminal (_replace `{exercise-folder-location}` below with your path_). +Test files usually end in `_test.py`, and are the same tests that run on the website when a solution is uploaded. + +Linux/MacOS +```bash +$ cd {path/to/exercise-folder-location} +``` + +Windows +```powershell +PS C:\Users\foobar> cd {path\to\exercise-folder-location} +``` + +
+ +Next, run the `pytest` command in your terminal, replacing `{exercise_test.py}` with the name of the test file: + +Linux/MacOS +```bash +$ python3 -m pytest -o markers=task {exercise_test.py} +==================== 7 passed in 0.08s ==================== +``` + +Windows +```powershell +PS C:\Users\foobar> py -m pytest -o markers=task {exercise_test.py} +==================== 7 passed in 0.08s ==================== +``` + + +### Common options +- `-o` : override default `pytest.ini` (_you can use this to avoid marker warnings_) +- `-v` : enable verbose output. +- `-x` : stop running tests on first failure. +- `--ff` : run failures from previous test before running other test cases. + +For additional options, use `python3 -m pytest -h` or `py -m pytest -h`. + + +### Fixing warnings + +If you do not use `pytest -o markers=task` when invoking `pytest`, you might receive a `PytestUnknownMarkWarning` for tests that use our new syntax: + +```bash +PytestUnknownMarkWarning: Unknown pytest.mark.task - is this a typo? You can register custom marks to avoid this warning - for details, see https://docs.pytest.org/en/stable/mark.html +``` + +To avoid typing `pytest -o markers=task` for every test you run, you can use a `pytest.ini` configuration file. +We have made one that can be downloaded from the top level of the Python track directory: [pytest.ini][pytest.ini]. + +You can also create your own `pytest.ini` file with the following content: + +```ini +[pytest] +markers = + task: A concept exercise task. +``` + +Placing the `pytest.ini` file in the _root_ or _working_ directory for your Python track exercises will register the marks and stop the warnings. +More information on pytest marks can be found in the `pytest` documentation on [marking test functions][pytest: marking test functions with attributes] and the `pytest` documentation on [working with custom markers][pytest: working with custom markers]. + +Information on customizing pytest configurations can be found in the `pytest` documentation on [configuration file formats][pytest: configuration file formats]. + + +### Extending your IDE or Code Editor + +Many IDEs and code editors have built-in support for using `pytest` and other code quality tools. +Some community-sourced options can be found on our [Python track tools page][Python track tools page]. + +[Pytest: Getting Started Guide]: https://docs.pytest.org/en/latest/getting-started.html +[Python track tools page]: https://exercism.org/docs/tracks/python/tools +[Python track tests page]: https://exercism.org/docs/tracks/python/tests +[pytest-cache]:http://pythonhosted.org/pytest-cache/ +[pytest-subtests]:https://github.com/pytest-dev/pytest-subtests +[pytest.ini]: https://github.com/exercism/python/blob/main/pytest.ini +[pytest: configuration file formats]: https://docs.pytest.org/en/6.2.x/customize.html#configuration-file-formats +[pytest: marking test functions with attributes]: https://docs.pytest.org/en/6.2.x/mark.html#raising-errors-on-unknown-marks +[pytest: working with custom markers]: https://docs.pytest.org/en/6.2.x/example/markers.html#working-with-custom-markers + +## Submitting your solution + +You can submit your solution using the `exercism submit rotational_cipher.py` command. +This command will upload your solution to the Exercism website and print the solution page's URL. + +It's possible to submit an incomplete solution which allows you to: + +- See how others have completed the exercise +- Request help from a mentor + +## Need to get help? + +If you'd like help solving the exercise, check the following pages: + +- The [Python track's documentation](https://exercism.org/docs/tracks/python) +- The [Python track's programming category on the forum](https://forum.exercism.org/c/programming/python) +- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5) +- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs) + +Should those resources not suffice, you could submit your (incomplete) solution to request mentoring. + +Below are some resources for getting help if you run into trouble: + +- [The PSF](https://www.python.org) hosts Python downloads, documentation, and community resources. +- [The Exercism Community on Discord](https://exercism.org/r/discord) +- [Python Community on Discord](https://pythondiscord.com/) is a very helpful and active community. +- [/r/learnpython/](https://www.reddit.com/r/learnpython/) is a subreddit designed for Python learners. +- [#python on Libera.chat](https://www.python.org/community/irc/) this is where the core developers for the language hang out and get work done. +- [Python Community Forums](https://discuss.python.org/) +- [Free Code Camp Community Forums](https://forum.freecodecamp.org/) +- [CodeNewbie Community Help Tag](https://community.codenewbie.org/t/help) +- [Pythontutor](http://pythontutor.com/) for stepping through small code snippets visually. + +Additionally, [StackOverflow](http://stackoverflow.com/questions/tagged/python) is a good spot to search for your problem/question to see if it has been answered already. + If not - you can always [ask](https://stackoverflow.com/help/how-to-ask) or [answer](https://stackoverflow.com/help/how-to-answer) someone else's question. \ No newline at end of file diff --git a/rotational-cipher/README.md b/rotational-cipher/README.md new file mode 100644 index 0000000..e86902c --- /dev/null +++ b/rotational-cipher/README.md @@ -0,0 +1,56 @@ +# Rotational Cipher + +Welcome to Rotational Cipher on Exercism's Python Track. +If you need help running the tests or submitting your code, check out `HELP.md`. + +## Instructions + +Create an implementation of the rotational cipher, also sometimes called the Caesar cipher. + +The Caesar cipher is a simple shift cipher that relies on transposing all the letters in the alphabet using an integer key between `0` and `26`. +Using a key of `0` or `26` will always yield the same output due to modular arithmetic. +The letter is shifted for as many values as the value of the key. + +The general notation for rotational ciphers is `ROT + `. +The most commonly used rotational cipher is `ROT13`. + +A `ROT13` on the Latin alphabet would be as follows: + +```text +Plain: abcdefghijklmnopqrstuvwxyz +Cipher: nopqrstuvwxyzabcdefghijklm +``` + +It is stronger than the Atbash cipher because it has 27 possible keys, and 25 usable keys. + +Ciphertext is written out in the same formatting as the input including spaces and punctuation. + +## Examples + +- ROT5 `omg` gives `trl` +- ROT0 `c` gives `c` +- ROT26 `Cool` gives `Cool` +- ROT13 `The quick brown fox jumps over the lazy dog.` gives `Gur dhvpx oebja sbk whzcf bire gur ynml qbt.` +- ROT13 `Gur dhvpx oebja sbk whzcf bire gur ynml qbt.` gives `The quick brown fox jumps over the lazy dog.` + +## Source + +### Created by + +- @krapes + +### Contributed to by + +- @akashsara +- @behrtam +- @cmccandless +- @Dog +- @dotrungkien +- @ikhadykin +- @lekum +- @N-Parsons +- @tqa236 + +### Based on + +Wikipedia - https://en.wikipedia.org/wiki/Caesar_cipher \ No newline at end of file diff --git a/rotational-cipher/rotational_cipher.py b/rotational-cipher/rotational_cipher.py new file mode 100644 index 0000000..60b1b94 --- /dev/null +++ b/rotational-cipher/rotational_cipher.py @@ -0,0 +1,63 @@ +""" +The rotational cipher, also sometimes called the Caesar cipher. + +The Caesar cipher is a simple shift cipher that relies on transposing +all the letters in the alphabet using an integer key between 0 and 26. +Using a key of 0 or 26 will always yield the same output due to modular +arithmetic. The letter is shifted for as many values as the value of the key. +""" + +import string + +LETTERS_LOWER: str = string.ascii_lowercase +LETTERS_UPPER: str = string.ascii_uppercase + + +def rotate(text: str, key: int) -> str: + """ + Rotate each letter in the text by the specified key using Caesar cipher. + + Non-alphabetic characters remain unchanged. The rotation wraps around + the alphabet (a->z, A->Z) using modular arithmetic. + + :param text: The input string to be rotated + :param key: The number of positions to shift each letter (0-25) + :return: The rotated string with letters shifted by key positions + + Examples: + >>> rotate("abc", 1) + "bcd" + >>> rotate("Hello, World!", 13) + "Uryyb, Jbeyq!" + """ + new_str: list[str] = [] + for char in text: + # Not a letter + if not char.isalpha(): + new_str.append(char) + else: + new_str.append(replace_char(char, key)) + # Convert to a string + return "".join(new_str) + + +def replace_char(char: str, key: int) -> str: + """ + Shifts the character by the specified key positions within its alphabet + (uppercase or lowercase). Uses modular arithmetic to wrap around the + alphabet. + + :param char: The alphabetic character to rotate + :param key: The number of positions to shift the character + :return: The rotated character in the same case as the input + """ + if char in LETTERS_UPPER: + new_index: int = LETTERS_UPPER.index(char) + key + if new_index < 26: + return LETTERS_UPPER[new_index] + return LETTERS_UPPER[new_index - 26] + + new_index = LETTERS_LOWER.index(char) + key + if new_index < 26: + return LETTERS_LOWER[new_index] + return LETTERS_LOWER[new_index - 26] diff --git a/rotational-cipher/rotational_cipher_test.py b/rotational-cipher/rotational_cipher_test.py new file mode 100644 index 0000000..6dde222 --- /dev/null +++ b/rotational-cipher/rotational_cipher_test.py @@ -0,0 +1,46 @@ +# pylint: disable=C0114, C0115, C0116, R0904 + +# These tests are auto-generated with test data from: +# https://github.com/exercism/problem-specifications/tree/main/exercises/rotational-cipher/canonical-data.json +# File last updated on 2023-07-19 + +import unittest + +from rotational_cipher import ( + rotate, +) + + +class RotationalCipherTest(unittest.TestCase): + def test_rotate_a_by_0_same_output_as_input(self): + self.assertEqual(rotate("a", 0), "a") + + def test_rotate_a_by_1(self): + self.assertEqual(rotate("a", 1), "b") + + def test_rotate_a_by_26_same_output_as_input(self): + self.assertEqual(rotate("a", 26), "a") + + def test_rotate_m_by_13(self): + self.assertEqual(rotate("m", 13), "z") + + def test_rotate_n_by_13_with_wrap_around_alphabet(self): + self.assertEqual(rotate("n", 13), "a") + + def test_rotate_capital_letters(self): + self.assertEqual(rotate("OMG", 5), "TRL") + + def test_rotate_spaces(self): + self.assertEqual(rotate("O M G", 5), "T R L") + + def test_rotate_numbers(self): + self.assertEqual(rotate("Testing 1 2 3 testing", 4), "Xiwxmrk 1 2 3 xiwxmrk") + + def test_rotate_punctuation(self): + self.assertEqual(rotate("Let's eat, Grandma!", 21), "Gzo'n zvo, Bmviyhv!") + + def test_rotate_all_letters(self): + self.assertEqual( + rotate("The quick brown fox jumps over the lazy dog.", 13), + "Gur dhvpx oebja sbk whzcf bire gur ynml qbt.", + )