Python - Repeating Code Using Loops - nested list, type annotations

Practical Programming
楽天ブックス 紀伊国屋書店

開発環境

• macOS Catalina - Apple (OS)
• Emacs (Text Editor)
• Windows 10 Pro (OS)
• Visual Studio Code (Text Editor)
• Python 3.7 (プログラミング言語)

Practical Programming: An Introduction to Computer Science Using Python 3.6 (Paul Gries(著)、Jennifer Campbell(著)、Jason Montojo(著)、Pragmatic Bookshelf)のChapter 9(Repeating Code Using Loops)、Exercise 4、5の解答を求めてみる。

コード

#!/usr/bin/env python3
from unittest import TestCase, main
from typing import List
print('4.')
alkaline_earth_metals: List[List] = [[4, 9.012],
                                     [12, 24.305],
                                     [20, 40.078],
                                     [38, 87.62],
                                     [56, 137.327],
                                     [88, 226]]

for number, weight in alkaline_earth_metals:
    print(f'number: {number}, weight: {weight}')


class MyTestCase(TestCase):

    def test_c1(self):
        number_and_weight = []
        for nw in alkaline_earth_metals:
            number_and_weight += nw
        self.assertEqual(number_and_weight,
                         [4, 9.012, 12, 24.305, 20, 40.078, 38, 87.62, 56, 137.327, 88, 226])

    def test_c2(self):
        number_and_weight = []
        for number, weight in alkaline_earth_metals:
            number_and_weight.append(number)
            number_and_weight.append(weight)
        self.assertEqual(number_and_weight,
                         [4, 9.012, 12, 24.305, 20, 40.078, 38, 87.62, 56, 137.327, 88, 226])


print('5.')


def mystery_function(values: List[List]) -> List:
    result: List[List] = []
    for sublist in values:
        result.append([sublist[0]])
        for i in sublist[1:]:
            result[-1].insert(0, i)
    return result


class MyTestCase5MysteryFunction(TestCase):
    def test_empty(self):
        self.assertEqual(mystery_function([]), [])

    def test_one(self):
        self.assertEqual(mystery_function(
            [[1, 2, 3, 4, 5]]), [[5, 4, 3, 2, 1]])

    def test_two(self):
        values: List[List] = [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]
        self.assertEqual(mystery_function(values),
                         [[5, 4, 3, 2, 1], [10, 9, 8, 7, 6]])

    def test_other(self):
        self.assertEqual(mystery_function([[1, 2], [3, 4], [5, 6], [7, 8, 9, 10]]),
                         [[2, 1], [4, 3], [6, 5], [10, 9, 8, 7]])


if __name__ == '__main__':
    main()

入出力結果(Zsh、PowerShell、Terminal、Jupyter(IPython))

% mypy sample4.py
Success: no issues found in 1 source file
% ./sample4.py -v
4.
number: 4, weight: 9.012
number: 12, weight: 24.305
number: 20, weight: 40.078
number: 38, weight: 87.62
number: 56, weight: 137.327
number: 88, weight: 226
5.
test_c1 (__main__.MyTestCase) ... ok
test_c2 (__main__.MyTestCase) ... ok
test_empty (__main__.MyTestCase5MysteryFunction) ... ok
test_one (__main__.MyTestCase5MysteryFunction) ... ok
test_other (__main__.MyTestCase5MysteryFunction) ... ok
test_two (__main__.MyTestCase5MysteryFunction) ... ok

----------------------------------------------------------------------
Ran 6 tests in 0.001s

OK
%