PCEP Practice Test 32 — 15 Questions

Question 1

A student is writing a program that stores the daily steps walked over a week in a list. She wants to determine whether any day had fewer than 1000 steps, and if so, report the first such day's index. Which approach correctly finds the index of the first value below 1000?

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

Accepted Answer

Use a for loop with range(len(steps)) and break when steps[i] < 1000, then use the loop variable i.. Finding the first element that satisfies a condition requires both the element and its position. Iterating over indices with range(len(steps)) provides the index, and breaking on the first match leaves the loop variable holding that index. Searching for the minimum, iterating over values, or counting qualifying days all answer different questions and cannot report the earliest qualifying index.

Answer

Use a while loop with a counter that increments only when the step count is below 1000.

Answer

Use a for loop over the list elements and break when the element is below 1000, then print the element itself.

Answer

Use steps.index(min(steps)) to locate the day with the fewest steps.

Question 2

A logistics team stores shipment data as `shipment = {'id': 'A17', 'weight_kg': 12.5, 'destination': 'Osaka'}`. A developer needs to retrieve the destination but wants the program to keep running and supply the string 'UNKNOWN' if the key is ever missing from a shipment record. Which statement should the developer use?

Accepted Answer

shipment.get('destination', 'UNKNOWN'). Reading a dictionary value without risking a KeyError requires a method that accepts a default, and dict.get is the standard tool for that. It returns the stored value when the key is present and the supplied fallback when it is not, without altering the dictionary. Methods that insert or remove keys change the record's contents, which the scenario does not permit.

Answer

shipment['destination'] or 'UNKNOWN'

Answer

shipment.pop('destination', 'UNKNOWN')

Answer

shipment.setdefault('destination', 'UNKNOWN')

Question 3

A Python developer is validating a list of sensor readings stored in `readings`. The developer needs to build a new list containing only readings that are strictly greater than 10. Which two code fragments correctly produce a list of only the values greater than 10? (Choose two.)

Accepted Answer

filtered = [r for r in readings if r > 10]. A list comprehension with a trailing `if r > 10` and the built-in `filter()` with a lambda both select exactly the elements satisfying the strict comparison, producing the required list. The other fragments either use an inclusive comparison that wrongly keeps 10, call a nonexistent list method, or use invalid comprehension syntax with an `else` clause in the filter position.

Answer

filtered = [r for r in readings if r > 10 else r]

Answer

filtered = [r for r in readings if r >= 10]

Answer

filtered = readings.filter(r > 10)

Question 4

A Python developer is writing a script that processes a list of temperatures in a loop. Inside the loop, a conditional block handles sub-zero readings by appending a warning to a report. The developer notices that the loop body is executing even for temperatures that are not sub-zero. Which statement about Python's `if`/`elif`/`else` structure explains why a block guarded by `if temp < 0:` should not execute for a temperature of 5?

Accepted Answer

The `if` block executes only when its condition evaluates to a truthy value; since `5 < 0` is False, the block is skipped.. Conditional blocks in Python execute based on the truth value of their condition, evaluated before the block runs. Because `5 < 0` is False, the guarded block is skipped and control moves on. The other statements misdescribe evaluation order, trigger conditions, or dependencies among sibling clauses, none of which match Python's top-down conditional evaluation model.

Answer

The `if` block executes whenever the loop variable is reassigned, regardless of the condition's truth value.

Answer

The `if` block executes only if a previous `elif` condition was also False, making it dependent on sibling clauses.

Answer

The `if` block executes for every iteration because Python evaluates conditions after running the block once.

Question 5

A software tester is examining a list of error codes: `errors = [404, 500, 403, 404, 200]`. She wants to determine if the code 404 appears in the list and print 'Found' if it does, otherwise 'Not found'. Which code correctly achieves this?

Accepted Answer

if 404 in errors:
    print('Found')
else:
    print('Not found'). The `in` operator is the correct tool for checking if an element exists in a list. It returns a boolean and does not raise errors. The other options either misuse the `in` operator, rely on `index()` which can raise exceptions and misinterpret index 0, or invert the logic with `count()`.

Answer

if errors.count(404) == 0:
    print('Found')
else:
    print('Not found')

Answer

if errors in 404:
    print('Found')
else:
    print('Not found')

Answer

if errors.index(404):
    print('Found')
else:
    print('Not found')

Question 6

A developer is building a simple inventory check. The list stock holds integers representing item quantities. He wants to append the string 'low' to a separate list alerts once for each quantity that is less than 5. Which code correctly populates alerts?

Accepted Answer

for q in stock: if q < 5: alerts.append('low'). Appending inside a loop with a conditional adds one entry per qualifying quantity, which matches the requirement of one 'low' per item below 5. Breaking after the first match stops too early, using any collapses the count to a single Boolean decision, and rebinding alerts with a comprehension replaces rather than extends the existing list.

Answer

if any(q < 5 for q in stock): alerts.append('low')

Answer

alerts = ['low' for q in stock if q < 5] appended to the existing alerts list.

Answer

for q in stock: if q < 5: alerts.append('low') break

Question 7

A logistics coordinator tracks delivery statuses in a list of strings. The coordinator wants to build a new list containing only the statuses that are not equal to `"delivered"`, preserving the original order. Which code fragment produces the desired list `pending`?

Accepted Answer

pending = [s for s in statuses if s != "delivered"]. Selecting all entries that differ from a target value calls for a comprehension whose condition compares each element with `!=`. That preserves order and includes every non-matching status. Inverting the comparison keeps the wrong subset, `remove` mutates and returns `None`, and testing the literal's truthiness yields nothing at all.

Answer

pending = statuses.remove("delivered")

Answer

pending = [s for s in statuses if not "delivered"]

Answer

pending = [s for s in statuses if s == "delivered"]

Question 8

A developer is auditing loop constructs in a Python script. Which TWO statements about `break`, `continue`, `else`, and `range` are correct in Python? (Choose two.)

Accepted Answer

`continue` skips the rest of the current iteration and immediately re-evaluates the loop condition or fetches the next item.. The `else` clause of a loop runs only on normal exhaustion, not after a `break`, which supports search idioms. `continue` ends the current iteration and moves to the next, re-evaluating or advancing as appropriate. The other statements misdescribe `break` as iteration-skipping, give `range` an inclusive upper bound, and claim `while` always runs once, all of which are incorrect for Python.

Answer

`break` exits only the current iteration and resumes with the next item.

Answer

A `while` loop always executes its body at least once, even if the condition is initially false.

Answer

`range(5)` produces the list `[0, 1, 2, 3, 4, 5]` when printed.

Question 9

A developer defines a function with the signature def configure(host, port=8080, protocol='http'). A call is made as configure('web01', protocol='https'). Which statement describes what happens?

Accepted Answer

The call succeeds; host receives 'web01', port keeps its default 8080, and protocol receives 'https'.. Positional arguments bind to parameters in order, while keyword arguments bind by name regardless of position. Here the single positional value fills host, the keyword protocol fills that named parameter, and port is simply omitted, so it retains its default. The call is valid and produces host='web01', port=8080, protocol='https'.

Answer

The call fails with a SyntaxError because default parameters must always be passed explicitly when any keyword argument is used.

Answer

The call fails with a TypeError because a positional argument cannot be combined with a keyword argument.

Answer

The call succeeds, but 'https' is assigned to port because keyword arguments fill parameters in declaration order.

Question 10

A developer is writing a function that should accept any number of positional arguments and return their sum. Which function definition correctly achieves this?

Accepted Answer

def sum_all(*args): return sum(args). The *args parameter collects any number of positional arguments into a tuple, which can then be summed using the built-in sum function. The other options either accept only a single iterable, collect keyword arguments instead, or incorrectly unpack the tuple when calling sum, leading to errors.

Answer

def sum_all(*args): return sum(*args)

Answer

def sum_all(**args): return sum(args)

Answer

def sum_all(args): return sum(args)

Question 11

A programmer is building a simple inventory tracker using a Python list named stock that contains integer quantities. They need to add 10 to every quantity in the list, modifying the list in place. Which code correctly performs this operation?

Accepted Answer

for i in range(len(stock)): stock[i] = stock[i] + 10. To modify a list in place, you must assign to individual elements using their indices. Using range(len(stock)) provides those indices, and stock[i] = stock[i] + 10 updates each element. The other options either leave the list unchanged, create a new list, or cause an error, so they do not satisfy the in-place requirement.

Answer

stock = [qty + 10 for qty in stock]

Answer

stock = stock + 10

Answer

for qty in stock: qty = qty + 10

Question 12

A developer wants to create a tuple that contains a single element, the integer 5. Which of the following expressions produces exactly that?

Accepted Answer

t = (5,). A single-element tuple requires a trailing comma to distinguish it from a parenthesized expression. The expression (5,) creates a tuple containing the integer 5, while (5) is just the integer. The tuple() constructor can also be used with an iterable, but not with a single integer. The two-element tuple is incorrect because it contains two items.

Answer

t = (5)

Answer

t = (5, 5)

Answer

t = tuple(5)

Question 13

A developer needs to count how many times each word appears in a list named words. The code starts with counts = {} and then iterates over the list. Which loop body correctly increments the count for each word, creating the key when it is first seen?

Accepted Answer

counts[word] = counts.get(word, 0) + 1. Counting occurrences requires reading a possibly missing key without raising an exception and then storing the incremented value. The get method supplies a fallback of 0 for absent keys, and assigning the sum back to the dictionary both creates and updates the entry. The other forms either raise KeyError on first sight of a word or misuse a dictionary method.

Answer

counts[word] += 1

Answer

counts.setdefault(word) + 1

Answer

counts.update(word, counts[word] + 1)

Question 14

A developer defines a tuple `config = ('localhost', 8080, True)`. Later, the code attempts `config[1] = 9090`. What happens when this line executes?

Accepted Answer

A TypeError is raised because tuple objects do not support item assignment.. Tuples are immutable, meaning their elements cannot be changed after the tuple is created. The statement config[1] = 9090 tries to assign to an index, which triggers a TypeError. No automatic rebinding or type-based exception occurs. To change a value, you must build a new tuple and assign it to the variable.

Answer

The tuple is updated in place, and config becomes ('localhost', 9090, True).

Answer

The assignment succeeds only if the new value is of the same type as the old value.

Answer

A new tuple is created automatically with the updated value, and config is rebound to it.

Question 15

A developer writes a function to calculate the area of a rectangle: def area(length, width): return length * width. They call it as area(5, 3). What is the result and why?

Accepted Answer

15, because the arguments are passed positionally, so length=5 and width=3.. Positional arguments are matched to parameters based on their order in the function call. The first argument binds to the first parameter, the second to the second, and so on. Since length and width are multiplied, area(5, 3) returns 15. No keyword arguments are necessary, and the function does not enforce keyword-only parameters.

Answer

15, but only if the arguments are passed as area(length=5, width=3).

Answer

A TypeError occurs because the function requires keyword arguments.

Answer

8, because the function adds the arguments instead of multiplying them.