PCPP1 Practice Test 12 — 15 Questions

Question 1

You wish to group several widgets together within a frame. Which widget acts as a container for this purpose?

Accepted Answer

tk.Frame(). The Frame widget is specifically designed as a container to group other widgets.

Answer

tk.Group()

Answer

tk.Box()

Answer

tk.Container()

Question 2

Which of the following describes the purpose of the __slots__ attribute in a class?

Accepted Answer

To improve performance and reduce memory usage.. __slots__ restricts the creation of new instance attributes and reduces memory footprint by preventing the creation of a per-instance __dict__.

Answer

To allow private attribute access.

Answer

To define the method resolution order.

Answer

To prevent inheritance.

Question 3

In the Factory pattern, what should you do if the requested type is unknown?

Accepted Answer

Raise a ValueError.. Raising a ValueError or a custom 'UnknownTypeException' is the standard way to handle invalid inputs in a factory.

Answer

Log the error and return the base class.

Answer

Return a default instance.

Answer

Return None.

Question 4

What is the difference between a class-level variable and an instance-level variable?

Accepted Answer

Class-level variables are shared by all instances.. A class-level variable is shared across all instances of the class, whereas an instance-level variable is specific to each object.

Answer

Instance-level variables cannot be modified.

Answer

Class-level variables are always constant.

Answer

Class-level variables are hidden from subclasses.

Question 5

You are parsing a JSON response that contains a large list of objects. Which technique is most memory-efficient for processing these objects?

Accepted Answer

Iterate through the list object after parsing. If you have control over the response, streaming the JSON or processing it iteratively (if supported by the parser) saves memory.

Answer

Convert the entire JSON to a string then split

Answer

Use the 'json.loads()' method on the full response

Answer

Use a custom regex to parse the JSON

Question 6

How do you properly handle a non-200 status code when using 'requests' if you want to avoid manual status code checking?

Accepted Answer

Use response.raise_for_status(). Calling response.raise_for_status() will raise an HTTPError exception if the status code indicates an error (4xx or 5xx).

Answer

Use a decorator on the request function

Answer

Check response.error

Answer

The library raises an exception by default

Question 7

When using configparser, how do you handle multiline values?

Accepted Answer

Indent the subsequent lines.. You indent lines following the initial line within the option.

Answer

Use a backslash at the end of each line.

Answer

Wrap them in triple quotes ('''...''').

Answer

Use the '
' escape character.

Question 8

You are using sqlite3 and need to enforce foreign key constraints. How do you enable them?

Accepted Answer

connection.execute('PRAGMA foreign_keys = ON'). You must execute the command 'PRAGMA foreign_keys = ON;' on the connection.

Answer

It is enabled by default.

Answer

connection.execute('SET FOREIGN_KEYS ON')

Answer

connection.enable_foreign_keys()

Question 9

Which TWO of the following are valid ways to read sections in a configparser object?

Accepted Answer

for section in parser.sections():. You can iterate over the object or use the sections() method.

Answer

for section in parser.get_all():

Answer

for section in parser.keys():

Answer

for section in parser.read():

Question 10

How do you set a specific font for a widget?

Accepted Answer

widget.config(font=('Arial', 12)). The 'font' parameter accepts a tuple or string defining font family, size, and style.

Answer

widget.set_font('Arial', 12)

Answer

widget.style('Arial', 12)

Answer

widget.font = 'Arial 12'

Question 11

Which THREE of the following are valid ways to pass arguments to a function called by a Tkinter button command?

Accepted Answer

command=lambda arg=arg1: my_func(arg). Using lambda or functools.partial are the standard ways to handle arguments in button commands.

Answer

command=my_func(arg1=value)

Answer

command=my_func(arg1)

Question 12

How do you define a property in a class to make it read-only?

Accepted Answer

Define a property with only @property, no @setter.. By defining the property with only a getter (using @property) and omitting the setter method.

Answer

Use the 'readonly' decorator.

Answer

Use the 'final' modifier.

Answer

Set the attribute to private.

Question 13

Which TWO of the following are valid ways to create a singleton in Python?

Accepted Answer

Using a base class with a custom __new__ method.. Modules are natural singletons, and metaclasses can be used to control instance creation.

Answer

Using a global variable that is not initialized.

Answer

Using a function that returns a new instance every call.

Answer

Using a standard class without any special methods.

Question 14

Which THREE of the following are potential pitfalls of the Singleton pattern in Python?

Accepted Answer

They introduce global state.. Singletons can be hard to test, cause hidden global state, and create difficulties in multi-threaded environments.

Answer

They cannot be used with inheritance.

Answer

They are always thread-safe.

Question 15

In the 'requests' library, which HTTP method is typically used to update an existing resource on a server?

Accepted Answer

PUT. The PUT method is standard for replacing or updating an existing resource at a specific URI.

Answer

POST

Answer

GET

Answer

DELETE