PCAP Practice Test 28 — 15 Questions

Question 1

You are developing a Python application that processes financial transactions. The application is structured as a package named `finance`. Inside `finance`, there are subpackages: `models`, `services`, and `utils`. The `services` subpackage contains a module `validator.py` that defines a function `validate_transaction()`. This function uses a helper function `check_amount()` defined in `utils.helpers`. The package is used by multiple other projects, and you want to ensure that importing `finance` does not accidentally expose internal helper functions. You also want to allow users to easily import the main validation function via `from finance import validate_transaction`. Which of the following approaches best achieves these goals?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

In `finance/__init__.py`, write `from .services.validator import validate_transaction`. Then users can call `finance.validate_transaction()`.. It imports the `validate_transaction` function directly into the `finance` package namespace via `from .services.validator import validate_transaction` in `finance/__init__.py`. This allows users to use `from finance import validate_transaction` as desired, while keeping internal helper functions like `check_amount` in `utils.helpers` unexposed, since they are not imported into the package's top-level namespace. This approach follows the principle of explicit imports and encapsulation.

Answer

In `finance/__init__.py`, write `from . import services` and `from .services import validator`. Then users can call `finance.services.validator.validate_transaction()`.

Answer

In `finance/__init__.py`, write `from .services import validator`. Then users can call `finance.validator.validate_transaction()`.

Answer

In `finance/__init__.py`, write `from .utils.helpers import *` and `from .services.validator import validate_transaction`.

Question 2

Which THREE of the following string methods can be used to split a string into a list of substrings? (Choose three.)

Accepted Answer

splitlines(). The `splitlines()` method splits a string at line boundaries (like 
, 
, or ) and returns a list of substrings, making it a valid method for splitting a string into a list. It is specifically designed for handling multi-line strings.

Answer

join()

Answer

partition()

Question 3

A developer wants to check if a string 'racecar' is a palindrome by comparing it to its reverse. Which code completes the task correctly?

Accepted Answer

s[::-1] == s. The slicing syntax `s[::-1]` creates a reversed copy of the string `s`, and comparing it to `s` with `==` checks if the string reads the same forwards and backwards, which is the definition of a palindrome. For the string 'racecar', `s[::-1]` returns 'racecar', so the comparison is `True`.

Answer

reversed(s) == s

Answer

s[::1] == s

Answer

s.reverse() == s

Question 4

Refer to the exhibit. The above log shows an unhandled exception that caused the program to crash. The developer wants to handle this exception and log the error without crashing. Which exception type should be caught in the main code to capture this specific error?

Accepted Answer

ValueError. The traceback shows that a ValueError was raised. To handle this specific exception, the code should catch ValueError. Catching Exception would also work but is less specific. Catching BaseException catches system-exit exceptions. OSError is unrelated.

Answer

BaseException

Answer

OSError

Answer

Exception

Question 5

What will be the output of the following code?
    try:
        print(1/0)
    except:
        print('error')
    else:
        print('no error')
    finally:
        print('done')

Accepted Answer

error
done. The code raises a ZeroDivisionError when attempting 1/0, which is caught by the bare except clause, printing 'error'. The else clause is skipped because an exception occurred. The finally clause always executes, printing 'done'. Thus the output is 'error' followed by 'done'.

Answer

no error
done

Answer

error
no error
done

Answer

done

Question 6

A Python project has the following directory structure:

project/
    __init__.py
    main.py
    subpackage/
        __init__.py
        module.py

Inside 'module.py', there is a function 'func' that needs to be imported in 'main.py'. The team wants to import 'func' using a relative import from 'main.py'. However, when they run 'python main.py' from the project root, they get an ImportError. What is the most likely reason?

Accepted Answer

Relative imports cannot be used in scripts executed directly as __main__.. When a Python script is executed directly (e.g., `python main.py`), its `__name__` is set to `"__main__"`, not the package name. Relative imports (e.g., `from .subpackage.module import func`) rely on the `__package__` attribute being set to the package hierarchy, which only happens when the module is imported as part of a package. Since `main.py` is run as the top-level script, it has no package context, causing an `ImportError`.

Answer

The 'project' directory does not contain an __init__.py file.

Answer

The function 'func' is not defined as a public function.

Answer

The module name 'module.py' contains a hyphen.

Question 7

Consider the following code:
result = ' '.join(['a', 'b', 'c'])
print(repr(result))
What is the output?

Accepted Answer

'a b c'. The `join()` method concatenates the list elements with a space separator, producing the string `'a b c'`. The `repr()` function returns a string representation that includes quotes, so the output is `'a b c'` (with single quotes). Option C is correct because it matches the exact output of `print(repr(result))`.

Answer

['a', 'b', 'c']

Answer

"a b c"

Answer

a b c

Question 8

Refer to the exhibit. A Python script uses re.split with a regex pattern. What is the output?

Accepted Answer

['one', 'two', 'three']. `re.split(r'\s+', 'one   two three')` splits the string on one or more whitespace characters (`\s+`). The pattern consumes all contiguous whitespace as a single delimiter, producing a list of the three non-empty substrings: `['one', 'two', 'three']`. No trailing empty string is included because the string does not end with whitespace.

Answer

['one   two three']

Answer

['one', 'two', 'three', '']

Answer

['one', ' ', 'two', ' ', 'three']

Question 9

Which TWO of the following string methods return a new string without modifying the original?

Accepted Answer

replace(). The `replace()` method returns a new string with all occurrences of a substring replaced by another substring, without altering the original string. Similarly, `strip()` returns a new string with leading and trailing whitespace (or specified characters) removed, leaving the original unchanged. Both methods are non-mutating because strings in Python are immutable.

Answer

index()

Answer

find()

Answer

count()

Question 10

Which TWO of the following are valid ways to read a file line by line without loading the entire file into memory?

Accepted Answer

for line in f:. Iterating directly over a file object with `for line in f:` reads one line at a time from the file's internal buffer, never loading the entire file into memory. This is the idiomatic and memory-efficient way to process large files line by line in Python.

Answer

lines = list(f)

Answer

contents = f.read().split('
')

Answer

lines = f.readlines()

Question 11

Match each list method to its effect.

Accepted Answer

append: Adds an element to the end of the list.. Common list methods: append adds an element to the end, extend adds all elements from an iterable, remove deletes the first occurrence of a value, pop removes an element by index, and sort arranges the list in ascending order by default.

Answer

pop: Removes the first occurrence of a specified value.

Answer

sort: Sorts the list in descending order.

Question 12

Drag and drop the steps to create a simple HTTP server using the http.server module in Python into the correct order.

Accepted Answer

Import http.server, define handler class, create HTTPServer instance, call serve_forever(). Creating an HTTP server involves importing http.server, defining a handler, overriding methods, creating an HTTPServer instance, and calling serve_forever().

Answer

Define handler class, import http.server, create HTTPServer instance, call serve_forever()

Answer

Import http.server, create HTTPServer instance, define handler class, call serve_forever()

Answer

Import http.server, define handler class, call serve_forever(), create HTTPServer instance

Question 13

Which TWO of the following are immutable in Python?

Accepted Answer

Tuple. Tuple (B) is immutable because once created, its elements cannot be added, removed, or changed. This is enforced by Python's internal structure: tuples are stored as a fixed-length array of PyObject pointers, and any attempt to modify them raises a TypeError.

Answer

Set

Answer

Dictionary

Answer

List

Question 14

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.. In Python, the 'from None' clause in a raise statement explicitly suppresses exception chaining. Normally, when an exception is raised inside an except block, Python automatically chains the new exception to the original one using the __cause__ attribute. Using 'raise NewException from None' sets __cause__ to None, which prevents the interpreter from displaying the original exception's traceback, so only the final 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 15

Which TWO of the following can be used to remove leading whitespace (spaces, tabs, newlines) from a string? (Choose exactly 2 correct answers.)

Accepted Answer

lstrip(). The `lstrip()` method removes all leading whitespace characters (spaces, tabs, newlines) from the left side of a string. `strip()` removes leading and trailing whitespace, so it also satisfies the requirement of removing leading whitespace. Both are built-in string methods in Python.

Answer

rstrip()

Answer

trim()

Answer

clean()