PCEP Practice Test 13 — 15 Questions

Question 1

A support technician is running a Python script that parses a configuration file and stores key-value pairs in a dictionary called 'config'. The script then uses these values to set application parameters. The configuration file is optional, and some expected keys may be missing. Currently, the script crashes with a KeyError when accessing a missing key. The technician needs to modify the script to safely retrieve a value or return 'N/A' if a key is missing. The script must remain efficient and readable. Which modification best achieves this?

Accepted Answer

Use config.get(key, 'N/A') instead of direct key access. Option B (config.get(key, 'N/A')) is the most efficient and readable approach. It directly returns the default if the key is missing, without raising an exception or performing multiple lookups. Option A uses try-except, which is less efficient and more verbose. Option C uses setdefault, which modifies the dictionary by adding the default key-value pair, which may not be desired. Option D requires an extra lookup and is more verbose.

Answer

Wrap each access in a try-except block to catch KeyError and assign 'N/A'

Answer

Use if key in config: value = config[key] else: value = 'N/A'

Answer

Use config.setdefault(key, 'N/A') before accessing

Question 2

What is the output of the code?

Accepted Answer

Key not found. The dictionary does not have a key 'debug', so config['debug'] raises KeyError, which is caught, printing 'Key not found'. Option A is correct. Option B would require a default value. Option C would require a different exception. Option D would require no exception.

Answer

AttributeError

Answer

The program exits with no output

Answer

None

Question 3

Which TWO of the following are valid methods that can be called on a tuple object? (Choose two.)

Accepted Answer

.index(). Tuples have only two methods: count and index. Options B and C are correct. Option A is a list method. Option D is a list method. Option E is a list method.

Answer

.pop()

Answer

.append()

Answer

.sort()

Question 4

A developer wants to use a tuple to store the names of the months. They attempt to change an element: months = ("Jan","Feb","Mar"); months[1] = "Februar". What is the result?

Accepted Answer

A TypeError is raised. Tuples are immutable; assignment raises TypeError. Option D is correct because it is the TypeError that occurs. Option A is wrong because tuples cannot be mutated. Option B is wrong because AttributeError is for attribute access, not assignment. Option C is wrong because ValueError is for incorrect value, not assignment.

Answer

The tuple is updated to ("Jan","Februar","Mar")

Answer

A ValueError is raised

Answer

An AttributeError is raised

Question 5

Which TWO of the following are true about function arguments in Python? (Choose two.)

Accepted Answer

Arguments can be passed by position or keyword.. Default arguments are evaluated at definition time (A). Arguments can be passed by position or keyword (C). Options B, D, E are false.

Answer

Default arguments are evaluated each time the function is called.

Answer

*args collects keyword arguments.

Answer

**kwargs collects positional arguments.

Question 6

What is the output of the following code?

def test():
    try:
        return 1
    finally:
        return 2

print(test())

Accepted Answer

2. The finally block always executes, and its return statement overrides any previous return. Thus, the function returns 2.

Answer

None

Answer

Error

Answer

1

Question 7

A function is designed to process a list and returns a modified list. The developer wants to avoid unintended side effects on the original list when it is passed as an argument. Which approach best ensures the original list remains unchanged?

Accepted Answer

Use None as default and create a new list inside the function. Option A is correct because using None as a default and creating a new list inside the function ensures that the default argument is not shared across calls. Option B is dangerous because mutable default arguments are shared. Option C uses a tuple, which is immutable but would not allow modifications. Option D uses a global variable, which introduces side effects.

Answer

Use a tuple as default

Answer

Use an empty list as default

Answer

Use a global variable as default

Question 8

A developer writes a function that appends an item to a list: def add_item(item, my_list=[]): my_list.append(item); return my_list. They call add_item(1) twice. What are the return values of the two calls?

Accepted Answer

[1] and [1,1]. Default arguments are evaluated only once at function definition. The same list is used each call. The first call returns [1], the second returns [1,1]. Option B is correct. Option A is wrong because the list is mutated. Option C is wrong because the second call adds to the same list. Option D is wrong because no TypeError occurs.

Answer

[1] and [1]

Answer

TypeError

Answer

[1] and [2]

Question 9

Which THREE of the following are valid dictionary methods? (Choose three.)

Accepted Answer

.values(). get, keys, and values are valid dictionary methods. push and append are not dictionary methods.

Answer

.append()

Answer

.push()

Question 10

A developer is writing a robust script that must handle file reading errors. The script should catch only I/O-related exceptions (e.g., FileNotFoundError, PermissionError) and let other exceptions propagate. Which exception handling structure is best suited?

Accepted Answer

Use multiple except blocks for specific exception types. Option D is correct because using multiple except blocks for specific exception types allows precise handling without catching unwanted exceptions. Option A and C use bare except or except: which catch SystemExit and KeyboardInterrupt, which is dangerous. Option B catches all exceptions that inherit from Exception, which is too broad and may catch unexpected errors.

Answer

Use a single bare except: clause

Answer

Use except: and then re-raise the exception

Answer

Use except Exception: as the only handler

Question 11

In a try-except block, a developer has two except clauses: except ValueError: and except: (bare except). If the code in the try block raises a ValueError, which except clause is executed?

Accepted Answer

The ValueError except clause. Python matches the first except clause that catches the exception. The specific except ValueError catches it before the bare except. Option A is correct. Option B is wrong because the bare except is only for uncaught exceptions. Options C and D are incorrect because only the first matching except runs.

Answer

Both in order

Answer

Neither; program crashes

Answer

The bare except clause

Question 12

Refer to the exhibit. What exception is raised when this code is executed?

Accepted Answer

ZeroDivisionError. Dividing by zero raises ZeroDivisionError. Option D is correct. Option A is a superclass but not the specific exception. Options B and C are irrelevant.

Answer

ValueError

Answer

ArithmeticError

Answer

TypeError

Question 13

What is the result of the following expression?

d = {'a': 1}
d.get('b', 0)

Accepted Answer

0. The get method of a dictionary returns the value for the key if it exists, otherwise returns the default argument. Since 'b' is not a key, it returns 0.

Answer

None

Answer

KeyError

Answer

1

Question 14

A developer wants to create a tuple containing a single integer value 5. Which code snippet correctly creates such a tuple?

Accepted Answer

t = (5,). Option B (t = (5,)) correctly creates a single-element tuple. The trailing comma is essential. Option A creates an integer, not a tuple. Option C assigns an integer to a variable. Option D creates a list, not a tuple.

Answer

t = [5]

Answer

t = (5)

Answer

t = 5

Question 15

A junior developer wrote a function that calculates the average of a list of numbers. Inside the function, they used a variable named 'list' to store the input parameter. Later, they tried to call the built-in list() function to convert a string to a list inside the same function, but it raised a TypeError. The error occurs because the name 'list' now refers to the parameter, not the built-in. The function must be fixed without changing its external behavior. Which solution is the best practice?

Accepted Answer

Rename the local variable to something else, like 'lst' or 'data'. Option B (rename the local variable to a non-conflicting name, such as 'lst' or 'data') is the simplest and most Pythonic solution. It avoids shadowing the built-in and makes the code clearer. Option A uses the global keyword but the built-in is not global; it's in builtins. Option C is overly complex for this situation. Option D is vague and does not provide a concrete fix.

Answer

Use the global keyword to refer to the built-in list

Answer

Use the builtins module (import builtins; builtins.list()) to call the built-in

Answer

Remove the local variable and use the input parameter directly