diff --git a/python/matrix/.exercism/metadata.json b/python/matrix/.exercism/metadata.json new file mode 100644 index 0000000..929001b --- /dev/null +++ b/python/matrix/.exercism/metadata.json @@ -0,0 +1 @@ +{"track":"python","exercise":"matrix","id":"333863d5a8b9424fb72285ff1899f266","url":"https://exercism.io/my/solutions/333863d5a8b9424fb72285ff1899f266","handle":"DmitryKokorin","is_requester":true,"auto_approve":false} \ No newline at end of file diff --git a/python/matrix/README.md b/python/matrix/README.md new file mode 100644 index 0000000..e376e94 --- /dev/null +++ b/python/matrix/README.md @@ -0,0 +1,94 @@ +# Matrix + +Given a string representing a matrix of numbers, return the rows and columns of +that matrix. + +So given a string with embedded newlines like: + +```text +9 8 7 +5 3 2 +6 6 7 +``` + +representing this matrix: + +```text + 1 2 3 + |--------- +1 | 9 8 7 +2 | 5 3 2 +3 | 6 6 7 +``` + +your code should be able to spit out: + +- A list of the rows, reading each row left-to-right while moving + top-to-bottom across the rows, +- A list of the columns, reading each column top-to-bottom while moving + from left-to-right. + +The rows for our example matrix: + +- 9, 8, 7 +- 5, 3, 2 +- 6, 6, 7 + +And its columns: + +- 9, 5, 6 +- 8, 3, 6 +- 7, 2, 7 + +In this exercise you're going to create a **class**. _Don't worry, it's not as complicated as you think!_ + +- [**A First Look at Classes**](https://docs.python.org/3/tutorial/classes.html#a-first-look-at-classes) from the Python 3 documentation. +- [**How to Define a Class in Python**](https://realpython.com/python3-object-oriented-programming/#how-to-define-a-class-in-python) from the Real Python website. +- [**Data Structures in Python**](https://docs.python.org/3/tutorial/datastructures.html) from the Python 3 documentation. + + +## Exception messages + +Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to +indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not +every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include +a message. + +To raise a message with an exception, just write it as an argument to the exception type. For example, instead of +`raise Exception`, you should write: + +```python +raise Exception("Meaningful message indicating the source of the error") +``` + +## Running the tests + +To run the tests, run `pytest matrix_test.py` + +Alternatively, you can tell Python to run the pytest module: +`python -m pytest matrix_test.py` + +### Common `pytest` options + +- `-v` : enable verbose output +- `-x` : stop running tests on first failure +- `--ff` : run failures from previous test before running other test cases + +For other options, see `python -m pytest -h` + +## Submitting Exercises + +Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/matrix` directory. + +You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`. + +For more detailed information about running tests, code style and linting, +please see [Running the Tests](http://exercism.io/tracks/python/tests). + +## Source + +Warmup to the `saddle-points` warmup. [http://jumpstartlab.com](http://jumpstartlab.com) + +## Submitting Incomplete Solutions + +It's possible to submit an incomplete solution so you can see how others have completed the exercise. diff --git a/python/matrix/matrix.py b/python/matrix/matrix.py new file mode 100644 index 0000000..e3d9e6e --- /dev/null +++ b/python/matrix/matrix.py @@ -0,0 +1,16 @@ +class Matrix: + def __init__(self, matrix_string): + self.rows = [[int(s) for s in row_string.split()] + for row_string in matrix_string.split('\n')] + + def row(self, index): + if index < 1: + raise ValueError("Row index must be no less than 1") + + return self.rows[index - 1] + + def column(self, index): + if index < 1: + raise ValueError("Row index must be no less than 1") + + return [row[index - 1] for row in self.rows] diff --git a/python/matrix/matrix_test.py b/python/matrix/matrix_test.py new file mode 100644 index 0000000..9176dd9 --- /dev/null +++ b/python/matrix/matrix_test.py @@ -0,0 +1,43 @@ +import unittest + +from matrix import Matrix + +# Tests adapted from `problem-specifications//canonical-data.json` + + +class MatrixTest(unittest.TestCase): + def test_extract_row_from_one_number_matrix(self): + matrix = Matrix("1") + self.assertEqual(matrix.row(1), [1]) + + def test_can_extract_row(self): + matrix = Matrix("1 2\n3 4") + self.assertEqual(matrix.row(2), [3, 4]) + + def test_extract_row_where_numbers_have_different_widths(self): + matrix = Matrix("1 2\n10 20") + self.assertEqual(matrix.row(2), [10, 20]) + + def test_can_extract_row_from_non_square_matrix_with_no_corresponding_column(self): + matrix = Matrix("1 2 3\n4 5 6\n7 8 9\n8 7 6") + self.assertEqual(matrix.row(4), [8, 7, 6]) + + def test_extract_column_from_one_number_matrix(self): + matrix = Matrix("1") + self.assertEqual(matrix.column(1), [1]) + + def test_can_extract_column(self): + matrix = Matrix("1 2 3\n4 5 6\n7 8 9") + self.assertEqual(matrix.column(3), [3, 6, 9]) + + def test_can_extract_column_from_non_square_matrix_with_no_corresponding_row(self): + matrix = Matrix("1 2 3 4\n5 6 7 8\n9 8 7 6") + self.assertEqual(matrix.column(4), [4, 8, 6]) + + def test_extract_column_where_numbers_have_different_widths(self): + matrix = Matrix("89 1903 3\n18 3 1\n9 4 800") + self.assertEqual(matrix.column(2), [1903, 3, 4]) + + +if __name__ == "__main__": + unittest.main()