Summary  
This chapter covers Python’s string slicing syntax, showing how to extract substrings by specifying start, end, and step indices and how to use open-ended slicing patterns. It explains both fixed-range slicing and omitting components for flexible extraction.

General domain of usage  
Text processing

import unittest

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)


class TestUserCode(unittest.TestCase):
    # Expected values based on the given starter data
    EXP_NAME_CLEAN = "Ada Lovelace"
    EXP_HAS_QUICK = True
    EXP_INSIDE_PARENS = "quick"
    EXP_O_COUNT = 4
    EXP_DOMAIN = "example.com"
    EXP_SEP = " | "
    EXP_REPORT = f"{EXP_NAME_CLEAN}{EXP_SEP}{EXP_DOMAIN}{EXP_SEP}{EXP_O_COUNT}"

    def test_name_clean_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, "name_clean"),
            "The `name_clean` variable is declared.",
            "Expected `name_clean` to be declared."
        )

    def test_name_clean_value(self):
        import user_code
        try:
            actual = user_code.name_clean
            condition = actual == self.EXP_NAME_CLEAN
            failure = f"Expected `name_clean` to be `{self.EXP_NAME_CLEAN}`, but got `{actual}`."
        except AttributeError:
            condition = False
            failure = "Expected `name_clean` to be declared."
        _dynamic_test(
            self,
            condition,
            f"The `name_clean` value is `{self.EXP_NAME_CLEAN}`.",
            failure
        )

    def test_has_quick_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, "has_quick"),
            "The `has_quick` variable is declared.",
            "Expected `has_quick` to be declared."
        )

    def test_has_quick_value(self):
        import user_code
        try:
            actual = user_code.has_quick
            condition = actual == self.EXP_HAS_QUICK
            failure = f"Expected `has_quick` to be `{self.EXP_HAS_QUICK}`, but got `{actual}`."
        except AttributeError:
            condition = False
            failure = "Expected `has_quick` to be declared."
        _dynamic_test(
            self,
            condition,
            f"The `has_quick` value is `{self.EXP_HAS_QUICK}`.",
            failure
        )

    def test_inside_parens_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, "inside_parens"),
            "The `inside_parens` variable is declared.",
            "Expected `inside_parens` to be declared."
        )

    def test_inside_parens_value(self):
        import user_code
        try:
            actual = user_code.inside_parens
            condition = actual == self.EXP_INSIDE_PARENS
            failure = f"Expected `inside_parens` to be `{self.EXP_INSIDE_PARENS}`, but got `{actual}`."
        except AttributeError:
            condition = False
            failure = "Expected `inside_parens` to be declared."
        _dynamic_test(
            self,
            condition,
            f"The `inside_parens` value is `{self.EXP_INSIDE_PARENS}`.",
            failure
        )

    def test_o_count_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, "o_count"),
            "The `o_count` variable is declared.",
            "Expected `o_count` to be declared."
        )

    def test_o_count_value(self):
        import user_code
        try:
            actual = user_code.o_count
            condition = actual == self.EXP_O_COUNT
            failure = f"Expected `o_count` to be `{self.EXP_O_COUNT}`, but got `{actual}`."
        except AttributeError:
            condition = False
            failure = "Expected `o_count` to be declared."
        _dynamic_test(
            self,
            condition,
            f"The `o_count` value is `{self.EXP_O_COUNT}`.",
            failure
        )

    def test_domain_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, "domain"),
            "The `domain` variable is declared.",
            "Expected `domain` to be declared."
        )

    def test_domain_value(self):
        import user_code
        try:
            actual = user_code.domain
            condition = actual == self.EXP_DOMAIN
            failure = f"Expected `domain` to be `{self.EXP_DOMAIN}`, but got `{actual}`."
        except AttributeError:
            condition = False
            failure = "Expected `domain` to be declared."
        _dynamic_test(
            self,
            condition,
            f"The `domain` value is `{self.EXP_DOMAIN}`.",
            failure
        )

    def test_report_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, "report"),
            "The `report` variable is declared.",
            "Expected `report` to be declared."
        )

    def test_report_value(self):
        import user_code
        try:
            actual = user_code.report
            condition = actual == self.EXP_REPORT
            failure = f"Expected `report` to be `{self.EXP_REPORT}`, but got `{actual}`."
        except AttributeError:
            condition = False
            failure = "Expected `report` to be declared."
        _dynamic_test(
            self,
            condition,
            f"The `report` value is `{self.EXP_REPORT}`.",
            failure
        )


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


test_main.py

Pythonの主要なデータ型について堅実な理解を深め、それらを効果的に扱う方法を学びます。数値、ブール値、文字列を探求し、型をまたいだ値の変換や比較を安全に行う方法を習得します。算術演算、論理演算、文字列操作を自信を持って実行し、クリーンで信頼性の高いPythonコードを書くための基礎的なスキルを身につけます。

Pythonの数値型の基本を学習します。整数型や浮動小数点型、算術演算や演算子の優先順位について解説します。実際の時間や予算の計算を通じて、切り捨て除算、剰余演算、mathモジュールの関数を練習します。

Booleanデータ型の基礎を理解し、比較演算子による等価性、同一性、真偽値の評価方法を学習します。論理演算子を用いて、実際のプログラミングにおける明確かつ正確な条件式を構築します。



Pythonの文字列の作成やインデックス指定から、スライス、検索、テキストのフォーマットまで、実践的に学習します。文字列がイミュータブルである理由を理解し、対話型プログラムのために効率的に新しい文字列を構築する方法を習得します。



Pythonの主要なデータ型間の変換方法、文字列を確実に比較するための大文字小文字や空白の正規化、Noneによる欠損値の扱いについて解説します。実際のプログラムで生データを扱う際にbytesやbytearrayを使用する場面についても学びます。



チャレンジ：スライスと検索ドリル

解答