PCPP2 Practice Test 2 — 10 Questions

Question 1

Which THREE of the following are valid address families or socket types used with the Python socket module?

Accepted Answer

socket.AF_INET. AF_INET and AF_INET6 are common address families, while SOCK_STREAM and SOCK_DGRAM are standard socket types.

Answer

socket.AF_TCP

Answer

socket.SOCK_LOCAL

Question 2

You are designing a class hierarchy where a subclass needs to ensure it calls the constructor of its parent in a multiple inheritance scenario. Which mechanism is the standard Pythonic approach to handle this dynamically?

Accepted Answer

Using super().__init__(). super() is the standard way to delegate to the next class in the Method Resolution Order (MRO).

Answer

Explicitly calling ParentClass.__init__(self)

Answer

Manually tracking parent states in a registry

Answer

Using the __init__subclass__ hook

Question 3

You are handling large datasets and want to improve memory efficiency. Which Python feature allows you to iterate over a large sequence without loading it entirely into memory?

Accepted Answer

Generators. Generators provide a lazy evaluation mechanism to yield items one at a time.

Answer

Deepcopy

Answer

Set literals

Answer

List comprehensions

Question 4

When using a multiprocessing.Queue to share data between processes, what happens if the queue is full and you use the put() method without a timeout?

Accepted Answer

It blocks indefinitely until a slot becomes available.. By default, put() is a blocking operation that will wait until a slot is available if the queue is full.

Answer

It restarts the child process.

Answer

It raises a Full exception immediately.

Answer

It silently drops the data.

Answer

It overwrites the oldest item in the queue.

Question 5

Which TWO of the following are valid ways to execute a raw SQL query in SQLAlchemy?

Accepted Answer

Using engine.execute('SELECT * FROM table'). SQLAlchemy allows executing raw SQL via text() with engine.execute() or session.execute().

Answer

Using session.query(RawSQL('SELECT * FROM table'))

Answer

Using session.commit('SELECT * FROM table')

Answer

Using table.run('SELECT * FROM table')

Question 6

You are utilizing abstract base classes (ABCs). How do you enforce that a subclass implements a specific method?

Accepted Answer

Use the @abstractmethod decorator. The @abstractmethod decorator marks a method as requiring implementation in concrete subclasses.

Answer

Use a metaclass check

Answer

Raise NotImplementedError in the base class

Answer

Pass the method name to __init__

Question 7

Which command-line tool is typically used to inspect the contents of a SQLite database file?

Accepted Answer

sqlite3. The 'sqlite3' command-line interface is the standard tool to interact with .db files.

Answer

mysql

Answer

mongo

Answer

psql

Question 8

Which built-in function allows you to retrieve an attribute from an object by its string name?

Accepted Answer

getattr(). getattr() is the built-in function to access object attributes dynamically.

Answer

fetch()

Answer

getattribute()

Answer

access()

Question 9

You are using the multiprocessing.Process class and notice that child processes are not terminating cleanly. Which method should you call to ensure the main process waits for the child process to complete?

Accepted Answer

process.join(). The join() method blocks the calling thread until the process whose join() method is called terminates.

Answer

process.wait()

Answer

process.terminate()

Answer

process.close()

Answer

process.is_alive()

Question 10

Two threads are modifying a shared global integer. You want to ensure that only one thread modifies the integer at a time. Which synchronization primitive is most appropriate?

Accepted Answer

threading.Lock. A Lock (or Mutex) is the standard tool to ensure mutually exclusive access to a shared resource.

Answer

threading.Event

Answer

multiprocessing.Semaphore

Answer

multiprocessing.Queue

Answer

threading.Condition