python saddle points

python/saddle-points/README.md

@@ -0,0 +1,76 @@
+# Saddle Points
+
+Detect saddle points in a matrix.
+
+So say you have a matrix like so:
+
+```text
+    1  2  3
+  |---------
+1 | 9  8  7
+2 | 5  3  2     <--- saddle point at (2,1)
+3 | 6  6  7
+```
+
+It has a saddle point at (2, 1).
+
+It's called a "saddle point" because it is greater than or equal to
+every element in its row and less than or equal to every element in
+its column.
+
+A matrix may have zero or more saddle points.
+
+Your code should be able to provide the (possibly empty) list of all the
+saddle points for any given matrix.
+
+Note that you may find other definitions of matrix saddle points online,
+but the tests for this exercise follow the above unambiguous definition.
+
+## 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 the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)):
+
+- Python 2.7: `py.test saddle_points_test.py`
+- Python 3.4+: `pytest saddle_points_test.py`
+
+Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
+`python -m pytest saddle_points_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/saddle-points` 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
+
+J Dalbey's Programming Practice problems [http://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html](http://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html)
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.