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bkhl's solution

to High Scores in the Python Track

Published at Apr 29 2019 · 0 comments
Instructions
Test suite
Solution

Note:

This exercise has changed since this solution was written.

Manage a game player's High Score list.

Your task is to build a high-score component of the classic Frogger game, one of the highest selling and addictive games of all time, and a classic of the arcade era. Your task is to write methods that return the highest score from the list, the last added score and the three highest scores.

In this exercise, you're going to use and manipulate lists. Python lists are very versatile, and you'll find yourself using them again and again in problems both simple and complex.

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 the appropriate command below (why they are different):

  • Python 2.7: py.test high_scores_test.py
  • Python 3.4+: pytest high_scores_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 high_scores_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/high-scores 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

Tribute to the eighties' arcade game Frogger

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

high_scores_test.py

import unittest

from high_scores import latest, personal_best, personal_top_three

# Tests adapted from `problem-specifications//canonical-data.json` @ v4.0.0


class HighScoresTest(unittest.TestCase):
    def test_latest_score(self):
        scores = [100, 0, 90, 30]
        expected = 30
        self.assertEqual(latest(scores), expected)

    def test_personal_best(self):
        scores = [40, 100, 70]
        expected = 100
        self.assertEqual(personal_best(scores), expected)

    def test_personal_top_three_from_a_list_of_scores(self):
        scores = [10, 30, 90, 30, 100, 20, 10, 0, 30, 40, 40, 70, 70]
        expected = [100, 90, 70]
        self.assertEqual(personal_top_three(scores), expected)

    def test_personal_top_highest_to_lowest(self):
        scores = [20, 10, 30]
        expected = [30, 20, 10]
        self.assertEqual(personal_top_three(scores), expected)

    def test_personal_top_when_there_is_a_tie(self):
        scores = [40, 20, 40, 30]
        expected = [40, 40, 30]
        self.assertEqual(personal_top_three(scores), expected)

    def test_personal_top_when_there_are_less_than_3(self):
        scores = [30, 70]
        expected = [70, 30]
        self.assertEqual(personal_top_three(scores), expected)

    def test_personal_top_when_there_is_only_one(self):
        scores = [40]
        expected = [40]
        self.assertEqual(personal_top_three(scores), expected)


if __name__ == "__main__":
    unittest.main()
#!usr/bin/env python3


def personal_top_three(scores):
    return sorted(scores, reverse=True)[:3]


def personal_best(scores):
    return sorted(scores)[-1]


def latest(scores):
    return scores[-1]

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