Pythonの例外処理について解説

try:
    # 例外が発生する可能性のあるコード
except エラーの種類:
    # 例外が発生した場合の処理
else:
    # 例外が発生しなかった場合の処理
finally:
    # 例外の有無にかかわらず、必ず実行される処理

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Error: Division by zero is not allowed.")

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Error: Division by zero is not allowed.")
except ValueError:
    print("Error: Invalid value.")

try:
    result = 10 / 0
except:
    print("An error occurred.")

try:
    result = 10 / 0
except ZeroDivisionError as e:
    print(f"Error: {e}")

try:
    result = 10 / 2
except ZeroDivisionError:
    print("Error: Division by zero is not allowed.")
else:
    print(f"Result is {result}")

try:
    result = 10 / 2
except ZeroDivisionError:
    print("Error: Division by zero is not allowed.")
finally:
    print("This will always be executed.")

class CustomError(Exception):
    pass

try:
    raise CustomError("This is a custom error.")
except CustomError as e:
    print(f"CustomError: {e}")

try:
    try:
        result = 10 / 0
    except ZeroDivisionError as e:
        raise ValueError("A value error occurred.") from e
except ValueError as e:
    print(f"ValueError: {e}")
    print(f"Original exception: {e.__cause__}")

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Handling ZeroDivisionError")
    raise  # 再スロー