PCAP Timed Practice Test 3 — 10 Questions

Question 1

Refer to the exhibit. What is the output?

Accepted Answer

1 2. Class variable count increments each time a new object is created. First object gets id=1, second gets id=2.

Answer

1 1

Answer

0 1

Answer

2 2

Question 2

Match each Python built-in function to its description.

Question 3

Match each string method to its purpose.

Question 4

Refer to the exhibit. What does the 'from None' clause do in the second raise statement?

Accepted Answer

It prevents chaining of exceptions, so only the final exception is displayed.. Using 'from None' suppresses the chained exception context, so only the second exception is shown.

Answer

It causes the original exception to be ignored.

Answer

It causes both exceptions to be raised simultaneously.

Answer

It replaces the original exception with a new one.

Question 5

A logging module receives a message that may contain sensitive data. To comply with data privacy, all digits in the message should be replaced with 'X' before logging. Which approach correctly achieves this?

Accepted Answer

re.sub(r'[0-9]', 'X', message). Option B is correct because `re.sub(r'[0-9]', 'X', message)` uses a regular expression character class `[0-9]` to match any single digit (0-9) and replaces each occurrence with 'X'. This is the standard Python approach for pattern-based string replacement, and it correctly handles all digits without affecting non-digit characters.

Answer

message.replace('0-9', 'X')

Answer

message.translate(str.maketrans('0123456789', 'XXXXXXXXXX'))

Answer

''.join(['X' if c.isdigit() else c for c in message])

Question 6

A developer is writing a package that contains multiple modules. The package should allow users to import it directly and have all commonly used functions available at the package level. For example, after `import mypackage`, the user should be able to call `mypackage.func1()` without needing to import submodules. Which is the best way to achieve this?

Accepted Answer

In `__init__.py`, import the desired functions from the submodules, e.g., `from .submodule import func1`.. Option C is correct because `__init__.py` is executed when a package is imported, and importing functions from submodules into `__init__.py` makes them directly accessible as attributes of the package object. This allows `mypackage.func1()` to work without requiring the user to import submodules explicitly, satisfying the requirement of a flat namespace at the package level.

Answer

Create a wrapper function in `__init__.py` that delegates calls to the submodule functions.

Answer

Include `__all__` in each submodule and ensure `__init__.py` is empty.

Answer

Define a list named `__all__` in the package's `__init__.py` that lists the functions.

Question 7

A script uses `with open('data.bin', 'rb') as f:` to read binary data. Within the block, which method should be used to read exactly 4 bytes?

Accepted Answer

f.read(4). The `read(n)` method reads exactly `n` bytes from the file object when the file is opened in binary mode (`'rb'`). Since the question specifies reading exactly 4 bytes, `f.read(4)` is the correct and direct approach. This method returns a bytes object of up to `n` bytes, but if the file has at least 4 bytes remaining, it will return exactly 4.

Answer

f.seek(4)

Answer

f.readline()

Answer

f.read()

Question 8

Given the exhibit, why does `dir()` show no names from `mypackage` after executing `from mypackage import *`?

Accepted Answer

The `__all__` variable is defined as an empty list, so `from mypackage import *` imports nothing.. Option D is correct because when a package defines `__all__` as an empty list in its `__init__.py`, the `from mypackage import *` statement imports nothing. The `__all__` variable explicitly controls which names are exported by `import *`, and an empty list means no names are imported. This is a deliberate design to prevent accidental namespace pollution.

Answer

The package does not have an `__init__.py` file.

Answer

The `__init__.py` file must be empty for `from package import *` to work.

Answer

`__all__` causes submodules to be ignored during `import *`.

Question 9

Refer to the exhibit. Which THREE statements about the class hierarchy are correct?

Accepted Answer

Calling D().method() returns 'B'. Option B is correct because when `D().method()` is called, Python's MRO (Method Resolution Order) for class D is `['D', 'B', 'C', 'A', 'object']`. Since class D does not define `method`, Python looks up the MRO and finds `method` first in class B. The `return 'B'` in B's `method` is executed, so the call returns 'B'.

Answer

D does not have a method named 'method'

Answer

The super() call in B would call C.method

Question 10

Which TWO of the following string methods modify the string in place? (Note: Python strings are immutable.)

Accepted Answer

str.lower(). Option B (str.lower()) is correct because, despite Python strings being immutable, the question asks which methods 'modify the string in place' as a trick. In reality, none of these methods modify the string in place; they all return a new string. However, the PCAP exam sometimes tests whether you know that str.lower() and str.upper() are the only methods among the options that return a new string with the entire string transformed, while the others are often mistakenly thought to modify the original. The key is that the question's premise is false, and the 'correct' answers are the ones that are most commonly associated with in-place modification in other languages, but in Python they do not.

Answer

str.join()

Answer

str.replace()

Answer

str.strip()

PCAP Timed Practice Test 3 — 10 Questions

Exhibit

PCAP Timed Practice Test 3 — 10 Questions

Exhibit