Merge branch '2024_tt_custom_exceptions'

2024/tuesday_tips/custom_exceptions/basic_example.py

@@ -0,0 +1,25 @@
+class Person:
+    def __init__(self, name: str):
+        self.name: str = name
+        self._age: int
+
+    @property
+    def age(self):
+        return self._age
+
+    @age.setter
+    def age(self, value: int):
+        if value < 0:
+            raise ValueError("Age cannot be negative")
+        self._age = value
+
+def main() -> None:
+    try:
+        person = Person("John")
+        person.age = -10
+        print(f"Name: {person.name}, age: {person.age}")
+    except ValueError as error:
+        print(f"Error occurred: {error}")
+
+if __name__ == "__main__":
+    main()

2024/tuesday_tips/custom_exceptions/custom_exceptions.py

@@ -0,0 +1,48 @@
+class WeightLimitExceededError(Exception):
+    """Raised when the weight limit of a container is exceeded."""
+
+    def __init__(self, limit: int, current: int):
+        super().__init__(f"Weight limit exceeded: limit= {limit}, current= {current}")
+        self.limit = limit
+        self.current = current
+
+
+class WeightNegativeError(Exception):
+    """Raised when the weight of an item is negative."""
+
+    def __init__(self, weight: int):
+        self.weight = weight
+        self.message = f"Weight cannot be negative: weight= {weight}"
+
+
+class Container:
+    def __init__(self, limit: int):
+        self.limit = limit
+        self.current_weight = 0
+
+    def load_item(self, weight: int):
+        if weight < 0:
+            raise WeightNegativeError(weight)
+
+        new_weight = self.current_weight + weight
+
+        if new_weight > self.limit:
+            raise WeightLimitExceededError(self.limit, new_weight)
+
+        self.current_weight = new_weight
+        print("Item loaded")
+
+
+def main() -> None:
+    try:
+        container = Container(limit=100)
+        container.load_item(50)  # This should work fine
+        container.load_item(-60)  # This will raise a WeightLimitExceededError
+    except WeightLimitExceededError as e:
+        print(e)
+    except WeightNegativeError as e:
+        print(e.message)
+
+
+if __name__ == "__main__":
+    main()

2024/tuesday_tips/custom_exceptions/data.txt

@@ -0,0 +1,4 @@
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. 
+Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. 
+Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. 
+Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

2024/tuesday_tips/custom_exceptions/else_clause_use_case.py

@@ -0,0 +1,17 @@
+def process(data: str) -> None:
+    print("Processing data")
+
+
+def main() -> None:
+    file = None
+    try:
+        file = open("data.txt", "r")
+        data = file.read()
+    except IOError:
+        print("Error reading file")
+    else:
+        # Process the data
+        process(data)
+    finally:
+        if file is not None:
+            file.close()

2024/tuesday_tips/custom_exceptions/exception_chaining.py

@@ -0,0 +1,17 @@
+def convert_to_integer(text: str) -> int:
+    try:
+        return int(text)
+    except ValueError as e:
+        raise TypeError("Conversion to integer failed") from e
+
+
+def main() -> None:
+    try:
+        print(convert_to_integer("abc"))
+    except Exception as e:
+        print(f"An error occurred: {e}")
+        print(f"Cause of the error: {e.__cause__}")
+
+
+if __name__ == "__main__":
+    main()

2024/tuesday_tips/custom_exceptions/exception_with_custom_data.py

@@ -0,0 +1,16 @@
+class CustomError(Exception):
+    def __init__(self, message: str, extra_data: dict[str, str]):
+        super().__init__(message)
+        self.extra_data = extra_data
+
+
+def main() -> None:
+    try:
+        raise CustomError("An error occurred", {"key": "value"})
+    except CustomError as e:
+        print(e)
+        print(e.extra_data)  # Prints: {'key': 'value'}
+
+
+if __name__ == "__main__":
+    main()

2024/tuesday_tips/custom_exceptions/how_to_use_exceptions.py

@@ -0,0 +1,27 @@
+class CarNotAvailableException(Exception):
+    pass
+
+
+def rent_car(car_type: str, days: int) -> int:
+    available_cars = ["sedan", "SUV", "hatchback"]
+    if car_type not in available_cars:
+        raise CarNotAvailableException(f"{car_type} is not available.")
+
+    # Calculate rental cost, etc.
+    rental_cost = days * 40  # Assume a fixed rate per day
+    return rental_cost
+
+
+def main() -> None:
+    try:
+        rent_car("SUB", 5)
+        print("Car rented successfully.")
+    except CarNotAvailableException as e:
+        print(e)
+        print("Please choose a different car type.")
+    finally:
+        print("Thank you for using our car rental service.")
+
+
+if __name__ == "__main__":
+    main()

2024/tuesday_tips/custom_exceptions/pyproject.toml

@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "custom-exceptions"
+version = "0.1.0"
+description = ""
+authors = ["Andreas Bergman <[email protected]>"]
+license = "MIT"
+readme = "README.md"
+
+[tool.poetry.dependencies]
+python = "^3.12"
+
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"