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question:# Advanced Class Design and Inheritance in Python Problem Statement You are required to design a series of classes to model a basic Library system. The core functionalities you need to implement include: 1. **Basic Class Definitions and Initialization**: - Define a `Book` class with attributes for title, author, and ISBN. - Define a `Library` class that holds a collection of books. 2. **Methods and Attribute Access**: - Implement methods in the `Library` class to add, remove, and search for books by title. - Implement a method to list all books in the library. 3. **Class and Instance Variables**: - Implement a class variable in the `Library` class to keep track of the total number of books. 4. **Inheritance**: - Define a `DigitalLibrary` class that inherits from `Library`. - Add a feature to `DigitalLibrary` to download books, and track the number of downloads for each book. 5. **Iterators and Generators**: - Implement an iterator in the `Library` class to iterate over all books. - Implement a generator method in the `Library` class to list books by a specific author. Constraints 1. The titles and authors are case-insensitive in searches but should preserve case in storage. 2. ISBN is unique for each book. 3. A book can be in only one library at any given time. # Input Format - The input will not be read from standard input but will be tested using instances of your classes and methods. # Output Format - Your methods should return or print appropriate outputs as specified. # Requirements 1. Define the `Book` class: ```python class Book: def __init__(self, title: str, author: str, isbn: str): # Initialize book attributes ``` 2. Define the `Library` class: ```python class Library: total_books = 0 def __init__(self): # Initialize the library def add_book(self, book: Book): # Add a book to the library def remove_book(self, isbn: str): # Remove a book from the library by ISBN def search_books_by_title(self, title: str): # Search for books by title def list_books(self): # List all books in the library ``` 3. Define the `DigitalLibrary` class: ```python class DigitalLibrary(Library): def __init__(self): # Initialize the digital library def download_book(self, isbn: str): # Download a book and track the number of downloads ``` 4. Implement iterator and generator in the `Library` class: ```python class Library: # Previous code... def __iter__(self): # Iterator for all books def books_by_author(self, author: str): # Generator for books by a specific author ``` # Example Usage ```python library = Library() book1 = Book("Title One", "Author A", "ISBN001") book2 = Book("Title Two", "Author B", "ISBN002") library.add_book(book1) library.add_book(book2) print(library.search_books_by_title("Title One")) # Output: ["Title One by Author A"] digital_library = DigitalLibrary() digital_library.add_book(book1) digital_library.download_book("ISBN001") ``` Your task is to implement these classes, their methods, and ensure the provided functionalities work as specified.
answer:class Book: def __init__(self, title: str, author: str, isbn: str): self.title = title self.author = author self.isbn = isbn def __str__(self): return f"{self.title} by {self.author}" class Library: total_books = 0 def __init__(self): self.books = {} def add_book(self, book: Book): if book.isbn not in self.books: self.books[book.isbn] = book Library.total_books += 1 def remove_book(self, isbn: str): if isbn in self.books: del self.books[isbn] Library.total_books -= 1 def search_books_by_title(self, title: str): return [book for book in self.books.values() if title.lower() in book.title.lower()] def list_books(self): return list(self.books.values()) def __iter__(self): self._iter_idx = 0 self._iter_books = list(self.books.values()) return self def __next__(self): if self._iter_idx < len(self._iter_books): result = self._iter_books[self._iter_idx] self._iter_idx += 1 return result else: raise StopIteration def books_by_author(self, author: str): for book in self.books.values(): if author.lower() in book.author.lower(): yield book class DigitalLibrary(Library): def __init__(self): super().__init__() self.downloads = {} def download_book(self, isbn: str): if isbn in self.books: if isbn not in self.downloads: self.downloads[isbn] = 0 self.downloads[isbn] += 1 return f"Downloading {self.books[isbn]}" else: return "Book not found."
question:# String Preparation and Validation You are required to implement a function `prepare_string` that prepares and validates a given Unicode string for use in internet protocols based on the Stringprep tables defined in RFC 3454. The function should follow these steps: 1. **Remove "commonly mapped to nothing" characters**: Use `stringprep.in_table_b1` to filter out these characters. 2. **Case mapping using Table B.2**: Map characters using `stringprep.map_table_b2`. 3. **Prohibited characters check**: Ensure the resulting string does not contain any characters from the following tables: - `tableC.1` (space characters): Combine `stringprep.in_table_c11` and `stringprep.in_table_c12`. - `tableC.2` (control characters): Combine `stringprep.in_table_c21` and `stringprep.in_table_c22`. - `tableC.3` (private use), `stringprep.in_table_c3` - `tableC.4` (non-character code points), `stringprep.in_table_c4` - `tableC.5` (surrogate codes), `stringprep.in_table_c5` - `tableC.6` (inappropriate for plain text), `stringprep.in_table_c6` - `tableC.7` (inappropriate for canonical representation), `stringprep.in_table_c7` - `tableD.1` (characters with bidirectional property "R" or "AL"), `stringprep.in_table_d1` If the final string contains prohibited characters, raise a `ValueError` with the message "Prohibited character found". # Function Signature ```python import stringprep def prepare_string(input_str: str) -> str: pass ``` # Input - `input_str` (str): The input Unicode string to be prepared. # Output - Returns a prepared and validated string (str) if all checks pass. # Constraints - The input string can include any Unicode characters. - The solution must handle strings up to 10,000 characters efficiently. # Example ```python try: result = prepare_string("Example string") print(result) # Output depends on the mappings and removals performed. except ValueError as ve: print(str(ve)) # If the string contains prohibited characters. ``` # Note Be sure to use the functions provided by the `stringprep` module to ensure compliance with the RFC 3454 requirements.
answer:import stringprep def prepare_string(input_str: str) -> str: This function prepares and validates a given Unicode string for use in internet protocols based on the Stringprep tables defined in RFC 3454. # Step 1: Remove "commonly mapped to nothing" characters mapped_str = ''.join( ch for ch in input_str if not stringprep.in_table_b1(ch) ) # Step 2: Case mapping using Table B.2 mapped_str = ''.join( stringprep.map_table_b2(ch) if stringprep.map_table_b2(ch) else ch for ch in mapped_str ) # Step 3: Prohibited characters check prohibited_checks = [ stringprep.in_table_c11, stringprep.in_table_c12, stringprep.in_table_c21, stringprep.in_table_c22, stringprep.in_table_c3, stringprep.in_table_c4, stringprep.in_table_c5, stringprep.in_table_c6, stringprep.in_table_c7, stringprep.in_table_d1 ] for ch in mapped_str: if any(check(ch) for check in prohibited_checks): raise ValueError("Prohibited character found") return mapped_str
question:# CGI Script Task You are tasked with creating a CGI script to handle form submissions for a basic contact form on a website. The form allows users to submit their name, email address, and a message. Additionally, users can upload a profile picture. Your script should validate the provided data and generate an appropriate HTML response. The form uses the POST method for submissions. Requirements 1. **Form Fields**: - `name`: Must be a non-empty string. - `email`: Must be a non-empty string and should contain the "@" character. - `message`: Must be a non-empty string. - `profile_pic`: Optional file upload for the user's profile picture. 2. **Validation**: - Ensure `name`, `email`, and `message` are present and non-empty. - Verify the `email` field contains an "@" character. - Handle cases where `profile_pic` may not be provided. 3. **Output**: - If any required fields are missing or invalid, generate an HTML response indicating the error with a proper message. - If all fields are valid, generate an HTML response displaying the provided data and indicating a successful submission. - If a profile picture is uploaded, display the file name and the number of lines in the picture file (assuming it's a text file for simplicity). Implementation Write a CGI script in Python following these steps: 1. **Import necessary modules:** ```python import cgi import cgitb cgitb.enable() # Enable for debugging during development ``` 2. **Create a `FieldStorage` instance to parse form data:** ```python form = cgi.FieldStorage() ``` 3. **Validation and Processing:** - Check for required fields and validate the email. - Check if a file is uploaded. - Count lines in the uploaded file if present. 4. **Generate HTML Response:** - Display errors if validation fails. - Display form data if validation is successful. - Include profile picture details if the file is uploaded. Constraints - The script should handle form submissions securely, avoiding any security risks like shell command injection. - The script should be executable on a standard web server configured to handle CGI scripts. Example Code Structure ```python import cgi import cgitb cgitb.enable() # Enable for debugging # Create instance of FieldStorage form = cgi.FieldStorage() # Retrieve form data name = form.getfirst("name", "").strip() email = form.getfirst("email", "").strip() message = form.getfirst("message", "").strip() profile_pic = form["profile_pic"] if "profile_pic" in form else None # Validation errors = [] if not name: errors.append("Name is required.") if not email or "@" not in email: errors.append("A valid email is required.") if not message: errors.append("Message is required.") # Output print("Content-Type: text/html") print() # end of headers # Generate HTML response if errors: print("<html><head><title>Form Error</title></head><body>") print("<h1>Form Error</h1>") for error in errors: print(f"<p>{error}</p>") else: print("<html><head><title>Form Submitted</title></head><body>") print("<h1>Form Submitted Successfully</h1>") print(f"<p>Name: {name}</p>") print(f"<p>Email: {email}</p>") print(f"<p>Message: {message}</p>") if profile_pic: if profile_pic.file: linecount = sum(1 for line in profile_pic.file) print(f"<p>Profile Picture: {profile_pic.filename} ({linecount} lines)</p>") print("</body></html>") ``` Implement the full script based on the provided structure and test it with different form submissions to ensure it works as expected.
answer:import cgi import cgitb cgitb.enable() # Enable for debugging def handle_form_submission(): # MIME header print("Content-Type: text/html") print() # end of headers # Create instance of FieldStorage form = cgi.FieldStorage() # Retrieve form data name = form.getfirst("name", "").strip() email = form.getfirst("email", "").strip() message = form.getfirst("message", "").strip() profile_pic = form["profile_pic"] if "profile_pic" in form else None # Validation errors = [] if not name: errors.append("Name is required.") if not email or "@" not in email: errors.append("A valid email is required.") if not message: errors.append("Message is required.") # Generate HTML response print("<html><head><title>Form Submission</title></head><body>") if errors: print("<h1>Form Error</h1>") for error in errors: print(f"<p>{error}</p>") else: print("<h1>Form Submitted Successfully</h1>") print(f"<p>Name: {name}</p>") print(f"<p>Email: {email}</p>") print(f"<p>Message: {message}</p>") if profile_pic: if profile_pic.file: linecount = sum(1 for line in profile_pic.file) print(f"<p>Profile Picture: {profile_pic.filename} ({linecount} lines)</p>") print("</body></html>") if __name__ == "__main__": handle_form_submission()
question:Objective Demonstrate your understanding of advanced bar plot generation using the Seaborn package. Problem Statement You are provided with a dataset named `tips`, which contains information related to restaurant bills and tips. Your task is to perform the following: 1. Load the tips dataset using Seaborn. 2. Create a bar plot showing the total bill amounts (`total_bill`) for each day of the week (`day`). 3. Add a second layer of grouping by the time of day (`time`). - Each bar should represent the average `total_bill` for each day of the week (`day`). 4. Modify the plot aesthetics as follows: - Show error bars with the standard deviation of the data. - Use different colors for each group (`time`). - Make sure the bars are transparent 30%. 5. Add text labels showing the average `total_bill` on top of each bar. 6. Save the plot as `tips_barplot.png`. Input and Output Formats **Input**: None (the dataset will be loaded from within the code). **Output**: A saved plot image named `tips_barplot.png`. Constraints - Ensure that the plot aesthetics are clear and the plot is saved with a high resolution (300 dpi). Example Although no exact output example is provided, ensure the plot adheres to the specified aesthetics and correctly represents the data as described. Performance Requirements The code should execute efficiently and produce the plot without significant delay. Function Implementation Implement the following function with the provided specifications: ```python import seaborn as sns import matplotlib.pyplot as plt def generate_tips_barplot(): # Load the dataset tips = sns.load_dataset("tips") # Create the bar plot with multiple groupings ax = sns.barplot(data=tips, x="day", y="total_bill", hue="time", ci="sd", alpha=0.7) # Add text labels ax.bar_label(ax.containers[0], fmt='%.2f', fontsize=10) ax.bar_label(ax.containers[1], fmt='%.2f', fontsize=10) # Save the plot plt.savefig("tips_barplot.png", dpi=300) # Execute the function generate_tips_barplot() ```
answer:import seaborn as sns import matplotlib.pyplot as plt def generate_tips_barplot(): Generates a bar plot for the 'tips' dataset showing total bill amounts for each day of the week, further grouped by the time of day. The plot includes error bars with the standard deviation, different colors for each group, and text labels showing the average 'total_bill' on top of each bar. The plot is saved as 'tips_barplot.png' with a resolution of 300 dpi. # Load the dataset tips = sns.load_dataset("tips") # Create the bar plot with multiple groupings plt.figure(figsize=(10, 6)) ax = sns.barplot(data=tips, x="day", y="total_bill", hue="time", ci="sd", alpha=0.7) # Add text labels with average total bill amount on top of each bar for container in ax.containers: ax.bar_label(container, fmt='%.2f', fontsize=10) # Save the plot plt.savefig("tips_barplot.png", dpi=300) plt.close() # Execute the function generate_tips_barplot()