PCAP Practice Test 16 — 15 Questions

Question 1

Consider the following code:

name = "Alice"
age = 30
print(f"{name} is {age} years old.")

What is the output of the above code?

Accepted Answer

Alice is 30 years old.. Given the code:

name = "Alice"
age = 30
print(f"{name} is {age} years old.")

The f-string correctly interpolates the variables, producing 'Alice is 30 years old.' Option D is correct. Option A incorrectly includes an extra comma after 30. Option B uses the literal string 'Name' instead of the variable name. Option C adds an extra period at the end.

Answer

Alice is 30, years old.

Answer

Name is 30 years old.

Answer

Alice is 30 years old..

Question 2

Given the code above, what is printed? Note: each backslash is a single character.

Accepted Answer

23. The string "C:\Users\John\Documents" uses double backslashes to represent literal backslashes. Each double backslash `\` is a single backslash character. Counting all characters: C, :, \, U, s, e, r, s, \, J, o, h, n, \, D, o, c, u, m, e, n, t, s = 23 characters. Thus, the length is 23.

Answer

21

Answer

22

Answer

24

Question 3

Which of the following expressions returns True if the string s contains only hexadecimal digits (0-9, a-f, A-F)?

Accepted Answer

all(c in '0123456789abcdefABCDEF' for c in s). It explicitly checks each character in the string against the set of valid hexadecimal digits (0-9, a-f, A-F) using the `all()` function. This ensures that every character is a hex digit, which is the precise requirement for a string to contain only hexadecimal digits.

Answer

s.isdigit() or s.isalpha()

Answer

s.isnumeric()

Answer

s.isalnum() and s.islower()

Question 4

A team is developing a system that must handle different types of documents (PDF, Word, etc.). Each document type has a unique parsing method. To avoid massive conditional logic, which OOP concept should be applied?

Accepted Answer

Polymorphism. Polymorphism allows different document types (PDF, Word, etc.) to be treated uniformly through a common interface (e.g., a `parse()` method) while each class implements its own parsing logic. This eliminates the need for conditional statements (like `if type == 'PDF'`) because the correct method is resolved at runtime via dynamic dispatch, which is exactly what the team needs to avoid massive conditional logic.

Answer

Encapsulation

Answer

Inheritance

Answer

Abstraction

Question 5

What will the above code output?

Accepted Answer

Index out of range. The code attempts to access an index that is outside the valid range of the string. In Python, strings are zero-indexed, so for a string of length n, valid indices are 0 to n-1. Accessing an index equal to or greater than the length raises an IndexError, which is exactly what 'Index out of range' describes.

Answer

The program runs without output.

Answer

The program crashes with an unhandled IndexError.

Answer

ValueError is raised.

Question 6

A class `Point` has an `__init__` that sets `self.x` and `self.y`. They want to compare points by equality (i.e., `p1 == p2` should work correctly). Which method should they implement?

Accepted Answer

`__eq__`. In Python, the `__eq__` method is the correct way to define equality comparison for objects. When you implement `__eq__(self, other)`, it is automatically called by the `==` operator, allowing `p1 == p2` to return a Boolean based on custom logic (e.g., comparing `self.x` and `self.y`). This is the standard Python protocol for equality testing.

Answer

`__same__`

Answer

`__compare__`

Answer

`__cmp__`

Question 7

A developer needs to extract the file extension from a string like 'report.pdf'. Which string method is most appropriate?

Accepted Answer

str.split('.')[-1]. `str.split('.')[-1]` splits the string at each dot and returns the last element, which is the file extension. This method works reliably for simple cases like 'report.pdf' and is a common Python idiom for extracting extensions.

Answer

str.find('.')

Answer

str.partition('.')[2]

Answer

str.rstrip('.pdf')

Question 8

An engineer is debugging an application that uses inheritance. The base class 'Vehicle' defines a method 'start()' that prints 'Vehicle started'. The subclass 'Car' overrides 'start()' to print 'Car started'. The code contains a function that accepts a Vehicle object and calls 'start()'. What is the output if a Car object is passed?

Accepted Answer

'Car started'. When a Car object is passed to a function expecting a Vehicle reference, Python uses dynamic dispatch (late binding) to call the overridden `start()` method defined in the Car class. Since the actual runtime type is Car, the overridden version executes, printing 'Car started'. This is a fundamental principle of polymorphism in Python.

Answer

'Car started Vehicle started'

Answer

'Vehicle started'

Answer

AttributeError

Question 9

A company has a shared internal library stored in a Git repository. Developers need to use this library in multiple projects without copying the code. Which approach is the most Pythonic and maintainable?

Accepted Answer

Package the library as a proper Python package and install it via pip in each project's virtual environment.. Packaging the library as a proper Python package and installing it via pip in each project's virtual environment follows the Python packaging standard (PEP 517/518) and the principle of explicit dependency management. This approach ensures versioning, isolation, and easy updates without modifying sys.path or relying on fragile filesystem links, making it the most maintainable and Pythonic solution.

Answer

Add the library's directory to sys.path in each project's main script.

Answer

Create a symbolic link to the library's directory inside each project.

Answer

Copy the library source code into each project's directory.

Question 10

Given the code: s = 'Python'; t = s; s = s + '3.0'. What is the value of t after these lines execute?

Accepted Answer

'Python'. Strings in Python are immutable. The assignment `t = s` makes `t` reference the same string object as `s`. When `s = s + '3.0'` executes, a new string object `'Python3.0'` is created and bound to `s`, while `t` still references the original string `'Python'`. Thus, `t` remains `'Python'`.

Answer

It raises an error because s was reassigned.

Answer

''

Answer

'Python3.0'

Question 11

A developer is building a simulation of different types of vehicles. They have a base class Vehicle with an attribute speed initialized in __init__. They also have a subclass Car that inherits from Vehicle and adds an attribute fuel_type. The developer wants to ensure that every time a Car object is created, it also initializes the speed attribute from the Vehicle class. Which approach should the developer use?

Accepted Answer

In Car.__init__, call Vehicle.__init__(self) manually.. In Python, when a subclass overrides __init__, the parent class's __init__ is not automatically called. To ensure the speed attribute from Vehicle is initialized, the developer must explicitly call Vehicle.__init__(self) inside Car.__init__. This is a fundamental requirement of Python's inheritance mechanism for proper initialization of inherited attributes.

Answer

Override the __new__ method of Vehicle.

Answer

Use the @staticmethod decorator for initialization.

Answer

In Car.__init__, define speed directly without calling parent's __init__.

Question 12

Which of the following best describes the immutability of strings in Python?

Accepted Answer

Strings cannot be changed after creation, but variables can be reassigned.. Strings in Python are immutable objects, meaning once a string is created, its contents cannot be changed. However, the variable referencing the string can be reassigned to point to a new string object. This distinction between mutability of the object and reassignment of the variable is fundamental to Python's data model.

Answer

Strings can be modified in place using indexing.

Answer

Strings are mutable but require special methods.

Answer

Strings cannot be reassigned.

Question 13

Which method of a file object reads the entire content of a text file as a single string?

Accepted Answer

read(). The `read()` method, when called without arguments or with a negative size, reads the entire contents of a file as a single string. This is the standard Python file object method for reading all text at once, returning a str object. It is the correct choice because the question explicitly asks for a method that returns the entire content as a single string.

Answer

readall()

Answer

readline()

Answer

readlines()

Question 14

A developer wants to create a string that contains the current year and month in the format 'YYYY-MM'. The year and month are stored in integer variables year and month. Which expression would produce the desired result?

Accepted Answer

f"{year}-{month:02d}". Uses an f-string with the format specifier `:02d` to zero-pad the month to two digits, ensuring that months 1-9 appear as '01', '02', etc. This produces the exact 'YYYY-MM' format from integer variables without manual conversion or padding.

Answer

year + '-' + month

Answer

str(year) + '-' + str(month)

Answer

'%s-%s' % (year, month)

Question 15

A package 'tools' has the structure: tools/__init__.py, tools/calc.py, tools/io.py. In __init__.py, the developer writes: from . import calc. A user tries: import tools; print(tools.add(1,2)). This fails with AttributeError. Why?

Accepted Answer

The add function is not imported into the tools package namespace.. The `__init__.py` file only imports the `calc` module itself into the `tools` package namespace, not the `add` function. When a user calls `tools.add(1,2)`, Python looks for `add` directly in the `tools` namespace, but it is not there — it is only accessible as `tools.calc.add`. The `from . import calc` statement binds the name `calc` to the module, not its contents.

Answer

The function add is not defined in calc.py.

Answer

Relative imports are not allowed in __init__.py files.

Answer

The user should use tools.calc.add instead.