PCPP-32-101 PCPP1 – Certified Professional Python Programmer Level 1 Practice Questions

copy.copy() performs a shallow copy. It creates a new list list_b, but the elements inside are references to the same objects as in list_a. Therefore, the nested list [3, 4] is shared. When list_a[2][0] is modified, the change is visible in list_b.

copy.deepcopy() performs a deep copy, recursively copying all objects. list_c gets a completely independent copy of the nested list, so it remains unaffected by the change to list_a.

The configparser module is the standard Python library for working with configuration files in the format of INI files. It allows you to read, write, and manipulate structured configuration data organized into sections with key-value pairs.

This principle, often attributed to Python's design philosophy, favors clarity and predictability. It suggests that for a given task, the language should make the best approach easy to discover and use, reducing ambiguity and cognitive load for developers reading the code. This enhances readability and maintainability.

The Singleton pattern ensures a class has only one instance and provides a global point of access to it. A common Pythonic implementation involves overriding the __new__ method. This method controls the object creation process. It can check if a class-level attribute holding the instance already exists; if not, it creates it using super().__new__(cls) and stores it, otherwise, it returns the existing instance.

Calling socket.shutdown(socket.SHUT_WR) signals to the client that the server is done sending data (a TCP FIN). The server can then enter a recv() loop. The client's TCP stack will acknowledge the data, and once the client closes its end, the server's recv() will return b'', indicating a graceful shutdown. This confirms the client has processed the FIN and, by extension, the preceding data. Simply calling close() can lead to a TCP RST (reset), potentially causing the client to lose data still in its receive buffer.

This is the correct approach. The class IntList inherits from list. It overrides the append method. Inside the new method, it first performs a type check using isinstance(). If the check fails, it raises an appropriate exception. If it passes, it uses super().append(value) to call the parent class's (list's) original append method to perform the actual append operation.

This is the correct implementation. A single StringVar (theme_var) is created to hold the state. Each Radiobutton is linked to this same variable via the variable option. The value option for each button specifies the string that will be stored in theme_var when that button is selected. Because they all share the same variable, selecting one automatically deselects the others.

The Portfolio class holding a collection of Asset objects is a classic example of Composition (a 'has-a' relationship). Since the collection can contain objects of subclasses like Stock and Bond, and the Portfolio can operate on them through the common Asset interface, this demonstrates Polymorphism. Inheritance is shown by Stock and Bond extending Asset, but the question specifically asks about the Portfolio's relationship.

To create a decorator that accepts arguments, you need a factory pattern. This is typically implemented with three levels of nested functions. The outermost function accepts the decorator's arguments (e.g., attempts=3) and returns the actual decorator. The middle function is the decorator itself, which accepts the function to be decorated. The innermost function is the wrapper that contains the new logic and calls the original function.

The raise NewException from OriginalException syntax is used for explicit exception chaining. It sets the __cause__ attribute on the new exception to the original one. This indicates that the new exception was raised in direct response to the original one, and both tracebacks are displayed to aid in debugging.