Accumulate
Implement the accumulate operation, which, given a collection and an
operation to perform on each element of the collection, returns a new
collection containing the result of applying that operation to each element of
the input collection.
Given the collection of numbers:
- 1, 2, 3, 4, 5
And the operation:
- square a number (
x => x * x)
Your code should be able to produce the collection of squares:
- 1, 4, 9, 16, 25
Check out the test suite to see the expected function signature.
Restrictions
Keep your hands off that collect/map/fmap/whatchamacallit functionality provided by your standard library! Solve this one yourself using other basic tools instead.
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:
raise Exception("Meaningful message indicating the source of the error")
Running the tests
To run the tests, run pytest accumulate_test.py
Alternatively, you can tell Python to run the pytest module:
python -m pytest accumulate_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/accumulate 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.
Source
Conversation with James Edward Gray II https://twitter.com/jeg2
Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.