
正規表現におけるグループ化と量指定子のスキルを強化するために、テキストから日付を抽出する関数を作成します。目的は、**「YYYY-MM-DD」**（例: `2024-06-15`）および **「DD/MM/YYYY」**（例: `15/06/2024`）の形式の日付を識別することです。関数は文字列を走査し、一致したすべての日付をリストで返す必要があります。この演習では、**グループ**、**量指定子**、および**オルタネーション**を活用して、複数の日付形式を確実にマッチさせる方法を練習します。


import unittest
import user_code
import ast
import re   
import unittest
import importlib
import io
from contextlib import redirect_stdout

class TestTask(unittest.TestCase):
    def test_example_output(self):
        import user_code

        importlib.reload(user_code)
        text = "The events are on 2024-06-15 and 15/06/2024."
        result = user_code.extract_dates(text)
        expected = ["2024-06-15", "15/06/2024"]
        _dynamic_test(
            self,
            isinstance(result, list) and result == expected,
            "Function returns correct list for mixed formats.",
            f"Expected {expected}, got {result}",
        )

    def test_multiple_dates(self):
        import user_code
        importlib.reload(user_code)
        text = "Dates: 2022-01-01, 31/12/2023, and 2020-05-10."
        result = user_code.extract_dates(text)
        expected = ["2022-01-01", "31/12/2023", "2020-05-10"]
        _dynamic_test(
            self,
            isinstance(result, list) and result == expected,
            "Function finds multiple dates in both formats.",
            f"Expected {expected}, got {result}",
        )

    def test_no_dates(self):
        import user_code
        importlib.reload(user_code)
        text = "There are no dates here."
        result = user_code.extract_dates(text)
        expected = []
        _dynamic_test(
            self,
            isinstance(result, list) and result == expected,
            "Function returns empty list when no dates present.",
            f"Expected {expected}, got {result}",
        )

    # def test_edge_cases(self):
    #     import user_code
    #     importlib.reload(user_code)
    #     text = "Start:2021-12-31End:01/01/2022More:2022-02-02!"
    #     result = user_code.extract_dates(text)
    #     expected = ["2021-12-31", "01/01/2022", "2022-02-02"]
    #     _dynamic_test(
    #         self,
    #         isinstance(result, list) and result == expected,
    #         "Function finds dates at string edges and with punctuation.",
    #         f"Expected {expected}, got {result}",
    #    )

    def test_invalid_dates(self):
        import user_code
        importlib.reload(user_code)
        text = "These are not dates: 2024-6-15, 5/6/2024, 20240615, 15-06-2024."
        result = user_code.extract_dates(text)
        expected = []
        _dynamic_test(
            self,
            isinstance(result, list) and result == expected,
            "Function does not match invalid date formats.",
            f"Expected {expected}, got {result}",
        )

    def test_overlapping_dates(self):
        import user_code
        importlib.reload(user_code)
        text = "2023-12-24/2023-12-25 and 24/12/2023/25/12/2023"
        result = user_code.extract_dates(text)
        expected = ["2023-12-24", "2023-12-25", "24/12/2023", "25/12/2023"]
        _dynamic_test(
            self,
            isinstance(result, list) and result == expected,
            "Function finds adjacent and overlapping dates.",
            f"Expected {expected}, got {result}",
        )

def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)

def normalize_text(text):
    text = text.lower()
    text = re.sub(r"\s{2,}", " ", text)
    text = re.sub(r"\s*([,:?])\s*", r"\1 ", text)
    return text.strip()

def change_var(code: str, var_name: str, value: str) -> str:
    tree = ast.parse(code)
    lines = code.splitlines()
    for i, node in enumerate(tree.body):
        if isinstance(node, ast.Assign):
            for target in node.targets:
                if isinstance(target, ast.Name) and target.id == var_name:
                    start_line = node.lineno - 1
                    line = lines[start_line]
                    indent = ' ' * (len(line) - len(line.lstrip()))
                    lines[start_line] = f"{indent}{var_name} = {value}"
                    next_line = len(lines)
                    for next_node in tree.body[i+1:]:
                        if hasattr(next_node, 'lineno'):
                            next_line = next_node.lineno - 1
                            break
                    if next_line > start_line + 1:
                        lines[start_line+1:next_line] = []
                    
                    return '\\n'.join(lines)
    return code

if __name__ == "__main__":
    unittest.main()


test_main.py

基本的なPythonの知識を持つ学習者向けに設計された、Pythonの正規表現に関する包括的なコースです。本コースでは、正規表現の構文、パターンマッチング、高度な機能、理論と実践的な課題を通じた応用方法を扱います。

Pythonにおける正規表現の基礎、基本構文、パターンマッチング、主要な正規表現関数について学習します。

グルーピング、量指定子、アンカー、置換技法を用いた正規表現のさらなる深掘り。

先読み／後読み、非貪欲マッチングなどの高度な正規表現機能を習得し、実際のテキスト処理問題に正規表現を適用します。

チャレンジ：さまざまな形式の日付を抽出する

チャレンジ：さまざまな形式の日付を抽出する

解答