PCEP Computer Programming and Python Fundamentals Practice Test 9 — 15 Questions

Question 1

A developer writes: print('Hello' + 5). What is the result?

Accepted Answer

TypeError. In Python, the + operator performs string concatenation only when both operands are strings. Attempting to concatenate a string ('Hello') with an integer (5) raises a TypeError because Python does not implicitly convert the integer to a string for concatenation. This is a fundamental type safety feature of the language.

Answer

Hello 5

Answer

SyntaxError

Answer

Hello5

Question 2

A script uses 'import math' then calls 'math.sqrt(-1)'. What is the outcome?

Accepted Answer

ValueError. `math.sqrt()` in Python's math module does not support negative arguments; it raises a `ValueError` when given a negative number, as the function is designed for real numbers only. The error message is 'math domain error', indicating the input is outside the domain of the mathematical function.

Answer

NaN

Answer

A complex number

Answer

AttributeError

Question 3

Which TWO statements correctly describe Python's dynamic typing?

Accepted Answer

The interpreter infers the type from the assigned value.. Option D is correct because Python is dynamically typed: when you write an assignment such as x = 42, the interpreter determines the type of the object (int) from the value on the right-hand side at runtime, without any explicit type declaration. Option E is correct because a name in Python is just a reference to an object, so the same variable can be rebound to an object of a different type later, e.g., x = 42 followed by x = 'hello' changes x from int to str at runtime. Option A is wrong because Python requires no type declarations; types are attached to objects, not to variable names. Option B is wrong because Python performs type checking at runtime, not at compile time (the CPython compiler only produces bytecode and does not enforce types). Option C is wrong because a variable's type is not fixed after assignment; rebinding the name to a new object of another type is perfectly legal.

Answer

Variable types must be declared before use.

Answer

Python checks types only at compile time.

Answer

A variable's type is fixed once assigned.

Question 4

What is the result of the following expression? 3 + 4 * 2 ** 3 // 5

Accepted Answer

9. The expression follows Python's operator precedence: exponentiation (`**`) has the highest precedence, then multiplication (`*`) and floor division (`//`) are evaluated left to right, and finally addition (`+`). First, `2 ** 3` computes to 8. Then `4 * 8` gives 32, and `32 // 5` yields 6 (floor division truncates toward negative infinity, but here it's positive). Finally, `3 + 6` equals 9. Thus, option A is correct.

Answer

7

Answer

6

Answer

11

Question 5

Given the code: my_list = [1, 2, 3, 4, 5]. What is the output of print(my_list[-3:-1])?

Accepted Answer

[3, 4]. Python list slicing with negative indices counts from the end of the list. my_list[-3:-1] starts at index -3 (value 3) and goes up to but does not include index -1 (value 5), so it returns [3, 4].

Answer

[4, 5]

Answer

[2, 3]

Answer

[3, 4, 5]

Question 6

What does the following code print? text = 'Hello World'; print(text.replace('o', '0').upper())

Accepted Answer

HELL0 W0RLD. The code first replaces all occurrences of 'o' with '0' in 'Hello World', resulting in 'Hell0 W0rld'. Then it applies the .upper() method, converting all characters to uppercase, yielding 'HELL0 W0RLD'. Therefore, the output is 'HELL0 W0RLD'.

Answer

hell0 w0rld

Answer

HELLO WORLD

Answer

Hell0 W0rld

Question 7

Which of the following is a floating-point literal?

Accepted Answer

3.14. `3.14` is a numeric literal with a decimal point, which Python interprets as a floating-point number. Floating-point literals represent real numbers and can be written with a decimal point or using scientific notation (e.g., `3.14e0`).

Answer

'3.14'

Answer

42

Answer

1+2j

Question 8

What is the output of the following code? try: print(1/0); except ZeroDivisionError: print('error'); finally: print('done')

Accepted Answer

error
done. The code attempts to divide 1 by 0, which raises a ZeroDivisionError. The except block catches this specific exception and prints 'error', then the finally block always executes, printing 'done'. The output is therefore 'error' followed by 'done' on separate lines.

Answer

error

Answer

done
error

Answer

1/0
done

Question 9

Which keyword is used to define a function in Python?

Accepted Answer

def. In Python, the `def` keyword is used to define a function, followed by the function name, parentheses, and a colon. This is a fundamental syntax rule in the Python language specification, and no other keyword or identifier is valid for this purpose.

Answer

func

Answer

function

Answer

define

Question 10

What does the following code output? for i in range(3): if i == 1: continue; print(i, end=' ')

Accepted Answer

0 2. The for loop iterates over range(3), which produces values 0, 1, and 2. When i equals 1, the continue statement skips the rest of the loop body for that iteration, so print(i, end=' ') is not executed for i=1. Thus, only 0 and 2 are printed, separated by a space, giving output '0 2'. Option B is correct.

Answer

1

Answer

0 1 2

Answer

0

Question 11

Consider the code: x = 10; def func(): x = 5; print(x); func(); print(x). What is the output?

Accepted Answer

5
10. Inside the function `func()`, the local variable `x` is assigned the value 5, so `print(x)` inside the function outputs 5. After the function call, the global `x` remains 10, so the final `print(x)` outside the function outputs 10. This demonstrates Python's scoping rules where assignments inside a function create a local variable unless declared global.

Answer

5
5

Answer

10
10

Answer

10
5

Question 12

Which TWO of the following are immutable data types in Python?

Accepted Answer

str. Option A (str) is correct because Python strings are immutable: once created, their characters cannot be changed in place, and any operation like concatenation or slicing returns a new string object. Option E (tuple) is correct because tuples are immutable sequences; after creation you cannot add, remove, or reassign their elements, and attempting to do so raises a TypeError. The unmarked options do not belong because set (B), dict (C), and list (D) are all mutable container types, meaning their contents can be modified in place via methods such as add(), update(), or append().

Answer

set

Answer

dict

Answer

list

Question 13

Which THREE of the following are valid ways to create a list in Python?

Accepted Answer

list((1, 2, 3)). Option A, list((1, 2, 3)), is correct because the list() constructor accepts any iterable — here a tuple — and returns a new list object [1, 2, 3]. Option B, [x for x in range(3)], is correct because a list comprehension is a valid literal-style expression that builds a list, producing [0, 1, 2]. Option C, [1, 2, 3], is correct because it is a direct list display (literal) using square brackets, which is the most basic way to create a list. Option D, (1, 2, 3), is not correct because parentheses with commas create a tuple, not a list. Option E, {1, 2, 3}, is not correct because curly braces create a set (or a dict if key-value pairs are used), not a list.

Answer

(1, 2, 3)

Answer

{1, 2, 3}

Question 14

You are a junior developer at a logistics company. Your team maintains a Python script that processes daily shipment data from a CSV file. The script reads the file, computes total weight per shipment, and writes results to a new CSV. Recently, the script started crashing sporadically with a 'ValueError: invalid literal for int() with base 10: 'NULL''. The CSV file sometimes contains the string 'NULL' in the weight column for missing values. The current code reads the weight column as: weight = int(row['weight']). Your team lead wants a robust fix that handles missing data gracefully without crashing, and also logs the line number for any problematic rows for later review. Which of the following approaches best meets these requirements?

Accepted Answer

Wrap the int conversion in a try-except block: try: weight = int(row['weight']); except ValueError: weight = 0; log the line number using a counter variable.. It uses a try-except block to catch the ValueError when int() fails on 'NULL', sets weight to 0 as a fallback, and logs the line number using a counter variable. This approach handles any unexpected non-numeric string (not just 'NULL'), making it robust against future data anomalies, and satisfies the requirement to log problematic rows for review.

Answer

Use the string method .isdigit(): if row['weight'].isdigit(): weight = int(row['weight']); else: weight = 0; no logging.

Answer

Read the entire file into a list, then use a list comprehension to convert weights: weights = [int(w) if w != 'NULL' else 0 for w in rows] without logging.

Answer

Add a check: if row['weight'] != 'NULL': weight = int(row['weight']); else: weight = 0; and log a warning. Do not use try-except.

Question 15

You are an IT support specialist for a university. A professor uses a Python script that analyzes exam scores from a text file. The script calculates the average score and prints it. Recently, the script outputs 'NaN' instead of a number. The relevant code is: scores = [float(line.strip()) for line in open('scores.txt')]; average = sum(scores) / len(scores); print(average). You inspect the scores.txt file and find that one line contains the word 'Absent' and another line is blank. The professor wants the script to ignore non-numeric lines and blank lines, and also print a warning if any line was skipped. Which of the following modifications to the script best achieves this?

Accepted Answer

Open the file, iterate over lines, use try-except to convert to float, if successful append to list else increment a skip counter. At the end, print the average and the number of skipped lines.. It uses a try-except block to safely attempt conversion of each line to float, incrementing a skip counter for lines that fail (e.g., 'Absent' or blank). After processing, it computes the average only from successfully converted scores and prints both the average and the number of skipped lines, meeting the professor's requirements exactly.

Answer

Read all lines, filter with a lambda that checks if line can be converted to int, then convert to float.

Answer

Use list comprehension with condition if line.strip() != '': scores = [float(line.strip()) for line in open('scores.txt') if line.strip() != '']

Answer

Check if line.strip().isdigit() before conversion, and skip if not.