PCEP Data Types, Variables, Basic I/O and Operators Practice Test 14 — 15 Questions

Question 1

Which of the following expressions evaluate to True? (Choose three.)

Accepted Answer

3 ** 2 == 9. Option A is correct because the exponentiation operator ** raises 3 to the power of 2, yielding 9, and 9 == 9 evaluates to True. Option B is correct because in Python, comparing a float and an int with == performs numeric value comparison: 4.0 and 4 represent the same numeric value, so 4.0 == 4 is True. Option D is correct because the in operator performs a substring membership test on strings, and the substring "Py" occurs at the start of "Python", so the expression is True. Option C is not correct because 10 % 3 returns the remainder 1 (not 0), so 1 == 0 is False. Option E is not correct because bool(0) evaluates to False, not True, since zero is a falsy value in Python.

Answer

10 % 3 == 0

Answer

bool(0)

Question 2

Given the following code, which of the following statements are true after execution? (Choose three.)

x = 10
y = 3.0
z = x / y
w = x // y

Accepted Answer

The expression x % y is valid.. Option A is correct because x % y uses the modulo operator on an int and a float, which is valid in Python and yields the float remainder 1.0. Option B is correct because x / y performs true division (10 / 3.0), producing the float value approximately 3.3333333333333335. Option E is correct because x // y performs floor division; with a float operand the result is a float, so 10 // 3.0 equals 3.0. Option C is not correct because w is a float (3.0), not an int, since one operand is a float. Option D is not correct because the / operator always returns a float in Python 3, not an integer.

Answer

The type of w is int.

Answer

The expression x / y returns an integer.

Question 3

A junior developer is writing a script to calculate the total cost of items in a shopping cart. The script uses variables item_price (float) and quantity (int). The code is:

item_price = 2.5
quantity = 3
total = item_price * quantity
print("Total: " + total)

When run, this code raises a TypeError. The developer is confused because the multiplication seems correct. What is the most likely issue and the correct fix?

Accepted Answer

The print function cannot concatenate a string with a float; convert total to string using str(total).. The `print` function in Python expects all arguments to be strings when using the `+` operator for concatenation. The variable `total` is a float (result of multiplying a float by an int), and Python does not implicitly convert it to a string. The error is a `TypeError: can only concatenate str (not 'float') to str`. The fix is to explicitly convert `total` to a string using `str(total)` before concatenation.

Answer

The variable total is being overwritten by the print statement; use a different variable name.

Answer

The multiplication should be written as int(item_price) * quantity to ensure integer result.

Answer

The variable names are too descriptive; rename them to a and b to avoid confusion.

Question 4

A data analyst needs to read two integers from the user and compute their average as a float. The current code:

a = int(input())
b = int(input())
avg = a + b / 2
print(avg)

The output is always incorrect when a=5 and b=7 (expected 6.0, actual 8.5). The analyst cannot identify the bug. What is the root cause and correct fix?

Accepted Answer

The addition and division have wrong operator precedence; use parentheses: (a + b) / 2.. In Python, the division operator `/` has higher precedence than addition `+`, so `a + b / 2` is evaluated as `a + (b / 2)`, not `(a + b) / 2`. For a=5 and b=7, this computes `5 + (7 / 2) = 5 + 3.5 = 8.5` instead of the expected `(5 + 7) / 2 = 12 / 2 = 6.0`. Adding parentheses around `a + b` forces the addition to occur first, yielding the correct average as a float.

Answer

The input function is not converting correctly; use float(input()) instead.

Answer

The print function is rounding the result; use print("{:.1f}".format(avg)).

Answer

The division operator / always returns an integer; use // instead.

Question 5

A system administrator writes a script to monitor disk usage. The script reads a percentage from a file as a string, e.g., "100". The code:

usage = open("usage.txt").read().strip()
if usage > 80:
    print("Warning: disk usage high")
else:
    print("Disk usage OK")

Even when usage.txt contains "100", the script prints "Disk usage OK". The admin expected "Warning". What is the problem and how to fix?

Accepted Answer

The file reading returns a string; convert usage to int before comparison.. The `read()` method returns the file content as a string. In Python, comparing a string to an integer with `>` performs lexicographic (character-by-character) comparison, not numeric comparison. For example, `"100" > 80` evaluates to `False` because `"1"` (ASCII 49) is less than `80` (integer), so the condition fails and the script prints "Disk usage OK". Converting the string to an integer with `int(usage)` before the comparison ensures numeric comparison works as intended.

Answer

The comparison operator > is incorrect; use >= instead.

Answer

The file is not properly closed; use with statement.

Answer

The strip() method removes newlines but not spaces; usage may have extra spaces.

Question 6

A student is learning Python and writes a program to compute the area of a rectangle. The code:

length = input("Enter length: ")
width = input("Enter width: ")
area = length * width
print("Area:", area)

When the user enters 5 and 3, the program crashes with a TypeError: can't multiply sequence by non-int of type 'str'. The student is puzzled because they thought input returns numbers. What is the correct explanation and fix?

Accepted Answer

The input function returns a string, so use int(input("Enter length: ")) and int(input("Enter width: ")).. The `input()` function in Python always returns a string, even if the user types a number. When you try to multiply two strings (or a string by a string), Python raises a `TypeError` because it cannot multiply sequences by non-integers. The fix is to explicitly convert the input to an integer using `int()` before performing arithmetic.

Answer

The error is due to variable names length and width conflicting with built-in functions; rename them to l and w.

Answer

The print function cannot handle the multiplication result because area is a string; convert area to int.

Answer

The error can be fixed by using the eval function to directly evaluate the input as Python code.

Question 7

A data scientist needs to read a list of floats from a file, one per line, and compute the sum. The current code:

total = 0.0
with open("data.txt") as f:
    for line in f:
        total = total + line
print(total)

When run, a TypeError occurs: unsupported operand type(s) for +: 'float' and 'str'. The scientist knows that line is a string. Which fix will correctly sum the numbers?

Accepted Answer

Change to: total = total + float(line.strip()). `float(line.strip())` converts the string read from the file (after removing any surrounding whitespace, including the newline character) into a float, which can then be added to the float variable `total`. The original error occurs because Python does not allow implicit addition of a string to a float.

Answer

Change to: total = total + eval(line)

Answer

Change to: total = total + line.strip()

Answer

Change to: total = total + int(line)

Question 8

A Python script contains the following code:

x = 0.1 + 0.2
y = 0.3
print(x == y)

What is printed?

Accepted Answer

False. Floating-point numbers in Python follow the IEEE 754 standard, so decimal values like 0.1, 0.2, and 0.3 are stored as approximations. Adding 0.1 and 0.2 yields a result that is not exactly equal to the stored approximation of 0.3. Consequently, the equality check returns False.

Answer

0.3

Answer

True

Answer

An error occurs because floats cannot be compared with ==.

Question 9

A student writes the following code:

name = "Alice"
age = 25
print("Name: " + name + ", Age: " + age)

What happens when the code runs?

Accepted Answer

A TypeError is raised because you cannot concatenate a string and an integer.. In Python, the + operator cannot combine a string and an integer. The expression attempts to concatenate the string literal with the integer variable age, which raises a TypeError. To fix this, the integer must be converted to a string using str(age) or formatted using an f-string or the format() method.

Answer

It raises a SyntaxError before execution.

Answer

It prints: Name: Alice, Age: age

Answer

It prints: Name: Alice, Age: 25

Question 10

A Python script contains the following assignment: `value = 5` followed by `result = value * '2'`. What is the value of `result` after these statements execute?

Accepted Answer

`'22222'`. The multiplication operator `*` behaves differently depending on operand types. When one operand is an integer and the other is a string, Python repeats the string that many times. With `value = 5` and string `'2'`, the result is `'22222'`. This is a common source of confusion for beginners who expect numeric multiplication or implicit type conversion. Recognizing the operand types is essential to predicting the outcome correctly.

Answer

A `TypeError` is raised.

Answer

`'10'`

Answer

`10`

Question 11

A Python script contains the following code:

num = 7
result = num ** 2
print(result)

What is the output?

Accepted Answer

49. The exponentiation operator ** raises the left operand to the power of the right operand. With num assigned 7, num ** 2 computes 7 squared, which is 49. The other options misinterpret the operator as multiplication, no operation, or an error, but none of those apply because both operands are integers and the operator is valid.

Answer

Error: unsupported operand type(s)

Answer

7

Answer

14

Question 12

A student is analyzing Python code and wants to understand the result of the expression `2 ** 3 ** 2` in Python 3. What value does this expression produce?

Accepted Answer

512. The exponentiation operator (**) in Python is right-associative, meaning that in a chain like 2 ** 3 ** 2, the rightmost operation is performed first. This gives 2 ** (3 ** 2) = 2 ** 9 = 512. Understanding associativity prevents errors when chaining exponentiation without parentheses.

Answer

36

Answer

128

Answer

64

Question 13

A cashier script stores a product's unit price as a string read from a barcode label: price = '4.50'. The developer must compute the total for 3 units and print a numeric result. Which code produces the value 13.5?

Accepted Answer

total = float(price) * 3. The price arrives as text, so it must be converted with float() before multiplication. float('4.50') becomes 4.5, and 4.5 * 3 evaluates to 13.5. Using int() fails on the decimal point, while string repetition produces concatenated text. The correct approach converts first, then computes.

Answer

total = price * 3

Answer

total = str(price) * 3

Answer

total = int(price) * 3

Question 14

A Python programmer writes the following code:

x = 5
y = 2
result = x / y
print(type(result))

What is printed?

Accepted Answer

. In Python 3, the division operator / performs true division and always returns a float, even if the result is a whole number. Therefore, 5 / 2 evaluates to 2.5, and type(result) is . The floor division operator // would return an integer if both operands are integers.

Answer

Answer

Answer

Question 15

A programmer writes the following code: `x = 7` then `y = 2` then `z = x / y`. What is the data type and value of `z`?

Accepted Answer

`float` with value `3.5`. In Python 3, the division operator `/` always returns a float, even when dividing two integers that yield a whole number. For `x = 7` and `y = 2`, the result is `3.5`, stored as a `float`. This behavior differs from Python 2, where `/` performed integer division for integers. The `//` operator performs floor division and returns an integer when both operands are integers, but that is not used here.

Answer

`int` with value `4`

Answer

`int` with value `3`

Answer

`float` with value `3.0`