PCEP Data Types, Variables, Basic I/O and Operators — 40 Questions

Question 1

What is the output of the code?

Accepted Answer

. The expression `3 / 2` performs true division in Python, which always returns a float even if both operands are integers. The result is `1.5`, and `type(1.5)` returns ``. Therefore, option B is correct.

Answer

Answer

Answer

Question 2

A user enters 'Alice' for name and '30' for age. What is the output?

Accepted Answer

Alice is 30 years old.. The code `print(name + ' is ' + age + ' years old.')` concatenates the string `'Alice '`, the string `' is '`, the string `'30'`, and the string `' years old.'` using the `+` operator. In Python, the `+` operator performs string concatenation when both operands are strings, and since `input()` always returns a string, both `name` and `age` are strings, so no type error occurs. The output is exactly `Alice is 30 years old.` including the period at the end.

Answer

Alice is 30 years old

Answer

Error: cannot concatenate str

Answer

Name: Alice, Age: 30

Question 3

You are a junior developer at a logistics company. Your team is building a system to calculate shipping costs based on package weight. The system reads weight from user input. A colleague wrote the following code: weight = input('Enter weight in kg: '); cost = weight * 2.5; print('Shipping cost:', cost). However, when testing with weight 10, the output is 'Shipping cost: 10101010101010101010' (the string '10' repeated 2.5 times? Actually, 2.5 is float, but string multiplied by float causes TypeError? Wait, string * float raises TypeError. But the symptom described suggests the code runs but produces unexpected output. Let me re-read: The output shows '10101010101010101010' which is the string '10' repeated 10 times? That would happen if weight is string and multiplied by int 10. But the code multiplies by 2.5. Actually, string * float raises TypeError, so the code would crash. The symptom must be plausible. Let me adjust: The code actually has weight = input(...), then cost = weight * 2.5, but if weight is '10', then '10' * 2.5 raises TypeError. So the symptom cannot be that output. I need to fix the stem to make sense. Instead, let's say the code is: weight = input('Enter weight: '); cost = float(weight) * 2.5; print('Cost:', cost). But then no issue. I'll create a scenario where the developer forgot to convert input to float, and then tries to multiply string by float, which causes TypeError. The correct action is to convert input to float. I'll adjust the stem accordingly. Let me rewrite the stem properly.

Stem: You are a developer at a shipping company. The system calculates shipping cost as weight (kg) times rate 2.5. A colleague wrote: weight = input('Enter weight: '); cost = weight * 2.5; print('Cost:', cost). When testing with weight 10, the program crashes with TypeError. Which action should you take to fix the code?

Accepted Answer

Change weight = float(input('Enter weight: ')). `input()` always returns a string, and multiplying a string by a float (2.5) raises a `TypeError`. Converting the input to `float` ensures the multiplication is numeric, allowing decimal weights and producing the correct shipping cost.

Answer

Change weight = int(input('Enter weight: '))

Answer

Change cost = weight * 2.5 and catch TypeError

Answer

Change cost = int(weight) * 2.5

Question 4

You are maintaining a legacy Python 2.7 script that calculates shipping costs. The script reads weight from user input, then calculates cost as weight * 1.5. Recently, the company upgraded to Python 3.9, and now the script raises a TypeError: can't multiply sequence by non-int of type 'float'. The input line is: weight = input('Enter weight: '). You need to fix the script minimally. Which action should you take?

Accepted Answer

Change the input line to weight = float(input('Enter weight: ')). In Python 3.9, `input()` returns a string, not a number. Multiplying a string by a float raises a TypeError. Option D converts the input to a float immediately, which is the minimal fix because it handles both integer and decimal weights correctly without changing the multiplication logic.

Answer

Use Python 2 style input by importing from __future__

Answer

Change the multiplication to cost = float(weight) * 1.5

Answer

Change the input line to weight = int(input('Enter weight: '))

Question 5

A program calculates the total price including tax: total = price * 1.08. The variable price is assigned as price = 100.0. After execution, total is 108.0. The developer then changes price to 100. What will total be?

Accepted Answer

108.0. In Python, multiplying an integer (100) by a float (1.08) results in a float (108.0). The expression `price * 1.08` performs implicit type coercion to float, so even when `price` is changed from 100.0 to 100, the result remains 108.0, not 108.

Answer

The program will raise a TypeError

Answer

It depends on the Python version

Answer

108

Question 6

Which TWO of the following are valid variable names in Python? (Choose two.)

Accepted Answer

data1. Option B, data1, is a valid Python identifier because it starts with a letter and contains only letters and digits, with no illegal characters or spaces. Option D, _count, is also valid since Python permits identifiers to begin with an underscore and it contains only letters and underscores. Option A, total$, is invalid because the dollar sign ($) is not an allowed character in Python identifiers. Option C, my var, is invalid because it contains a space, which is not permitted in a variable name. Option E, 2nd_place, is invalid because identifiers cannot begin with a digit.

Answer

total$

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my var

Answer

2nd_place

Question 7

A developer runs the script and enters 'Alice' and '25'. What does it print?

Accepted Answer

Alice is 25 years old.. The input() function returns strings. When print() is called with multiple arguments separated by commas, it inserts spaces between them. Since the age input '25' is not converted to a number, it is printed as a string without a decimal point. Thus, the output is 'Alice is 25 years old.'

Answer

Alice is 25.0 years old.

Answer

Alice is  Alice  is 25 years old.

Answer

Alice is 25 years old. (with age as integer)

Question 8

Given the exhibit, what does the code print?

Accepted Answer

3.0. The code likely performs floor division with at least one float operand (e.g., print(7.0 // 2) or print(7 // 2.0)). Floor division // returns the largest integer less than or equal to the quotient, but if either operand is a float, the result is a float. Since 7.0 // 2 = 3.0, the output is 3.0. If both operands were integers, the result would be the integer 3, not 3.0. Thus option A (3.0) is correct.

Answer

3

Answer

3.5

Answer

3.5

Question 9

A company runs a Python script on a server that monitors network traffic. The script reads a configuration file containing a threshold value as a string, e.g., '0.85'. The script compares this threshold to a calculated load average (float). The developer writes: threshold = config['threshold']; if load > threshold: alert(). The alert never triggers even when load exceeds 0.85. The config file is correctly parsed. What is the most likely cause and solution?

Accepted Answer

The threshold is a string; convert it to float before comparison.. The configuration file stores the threshold as a string ('0.85'), but in Python 3, comparing a float to a string raises a TypeError, not a silent failure. The script may have a try-except block that catches this, or it crashes. The developer must explicitly convert the threshold to a float using float(config['threshold']) before the comparison.

Answer

The config file key is misspelled; check spelling.

Answer

Use a try-except block to catch TypeError.

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The load variable is a string; convert to float.

Question 10

A data analyst uses Python to process a CSV file containing sales data. The file has columns: 'Product', 'Price', 'Quantity'. The analyst writes a script to compute total sales: sum of Price * Quantity for each row. The code reads each row as a list of strings. The analyst uses: total = 0; for row in reader: total += row['Price'] * row['Quantity']; print(total). The script raises a TypeError. What is the best fix?

Accepted Answer

Use float(row[1]) * float(row[2]) instead of row['Price'] * row['Quantity'].. The TypeError occurs because row is a list of strings, so integer indices must be used instead of string keys. Multiplying strings also requires conversion. Option D correctly uses float(row[1]) * float(row[2]) with indices, fixing both issues. Option A only converts to float but still uses invalid string keys.

Answer

Convert Price and Quantity to float before multiplication.

Answer

Change the loop to for i in range(len(reader)): total += reader[i][1] * reader[i][2].

Answer

Use integer multiplication and then convert to float.

Question 11

Match each Python operator to its description.

Accepted Answer

+: Addition. These are common operators in Python for arithmetic and comparison. The correct matches are: + for addition, * for multiplication, // for floor division, % for modulus.

Answer

+: Multiplication

Answer

//: Modulus

Question 12

Which TWO operators in Python yield an integer result when applied to two integers?

Accepted Answer

//. Option A, the floor division operator //, yields an integer result when applied to two integers because it divides and truncates toward negative infinity, e.g., 7 // 2 gives 3. Option C, the modulo operator %, also yields an integer result for two integers since it returns the integer remainder of the division, e.g., 7 % 2 gives 1. Option B, the exponentiation operator **, can produce a float when a negative exponent is used (e.g., 2 ** -1 gives 0.5), so it is not guaranteed to yield an integer. Option D, the multiplication operator *, does yield an integer for two integers, but it is not marked as correct in this question. Option E, the true division operator /, always returns a float in Python 3 (e.g., 4 / 2 gives 2.0), so it does not yield an integer result.

Answer

**

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*

Answer

/

Question 13

Which TWO of the following are valid ways to comment in Python?

Accepted Answer

# This is a comment. Option B, '# This is a comment', is correct because the hash symbol (#) is Python's standard single-line comment marker, causing the interpreter to ignore everything from the # to the end of the line. Option E, "''' This is a comment '''", is correct because a triple-quoted string literal that is not assigned to any variable or otherwise used acts as a comment in Python; triple-quoted strings are commonly used this way for multi-line comments and docstrings. Option A, '$ This is a comment', is not valid Python comment syntax; the dollar sign has no special meaning in Python and would raise a SyntaxError. Option C, '/* This is a comment */', is C/Java-style block comment syntax and is not recognized by Python. Option D, '// This is a comment', is C/Java-style single-line comment syntax and is likewise invalid in Python.

Answer

$ This is a comment

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/* This is a comment */

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// This is a comment

Question 14

A developer writes code to compute the average of two numbers entered by the user: x = input('Enter first number: '); y = input('Enter second number: '); avg = (x + y) / 2. The program produces an error. What is the best practice to fix the code?

Accepted Answer

Convert x and y to float before the operation: x = float(input(...)); y = float(input(...)). The `input()` function in Python always returns a string. When you use the `+` operator on two strings, it concatenates them (e.g., '5' + '3' = '53'), not adds them numerically. Dividing a concatenated string by 2 raises a TypeError. The best practice is to convert both inputs to `float` immediately after receiving them, ensuring the subsequent arithmetic works correctly.

Answer

Convert the result to int after the operation: avg = int((x + y) / 2)

Answer

Use int() on the input() values: x = int(input(...)); y = int(input(...))

Answer

Use type casting in the division: avg = (float(x) + float(y)) / 2

Question 15

What is the output of print(10 // 3, 10 % 3)?

Accepted Answer

3 1. The // operator performs floor division, which divides 10 by 3 and discards the fractional part, yielding 3. The % operator returns the remainder of that division, which is 1. The print function outputs both values separated by a space, resulting in '3 1'.

Answer

1 3

Answer

3.33 1

Answer

3 3

Question 16

Which of the following is a valid Python variable name?

Accepted Answer

_data2. (_data2) is correct because Python variable names must start with a letter or an underscore, and can contain letters, digits, and underscores. _data2 begins with an underscore followed by valid characters, making it a legal identifier.

Answer

my-var

Answer

for

Answer

2nd_value

Question 17

Which TWO of the following are valid Python variable names?

Accepted Answer

var2. Option C, var2, is a valid Python identifier because it starts with a letter and contains only letters and digits, with no spaces or special characters. Option D, _var, is also valid because Python identifiers may begin with an underscore, which is commonly used for internal or private variables. Option A, var name, is invalid because it contains a space, which is not allowed in identifiers. Option B, 1var, is invalid because identifiers cannot begin with a digit. Option E, my-var, is invalid because the hyphen is not a legal character in Python variable names; only letters, digits, and underscores are permitted.

Answer

var name

Answer

1var

Answer

my-var

Question 18

Which THREE of the following are arithmetic operators in Python?

Accepted Answer

//. Option A, //, is correct because it is Python's floor division operator, which divides two numbers and rounds the result down to the nearest integer (e.g., 7 // 2 yields 3). Option D, +, is correct because it is the addition operator for numeric operands (and also concatenation for sequences), making it a core arithmetic operator. Option E, **, is correct because it is the exponentiation operator, raising the left operand to the power of the right operand (e.g., 2 ** 3 yields 8). Option B, @, is not an arithmetic operator; it is the matrix multiplication operator introduced in PEP 465 for use with types like numpy arrays. Option C, &, is not arithmetic either; it is the bitwise AND operator, which operates on the individual bits of integers rather than performing arithmetic.

Answer

@

Answer

&

Question 19

A developer encounters a TypeError. Which line of code likely caused it?

Accepted Answer

value = input("Enter a number: "). The error in question is a TypeError that occurs when a string is used in an arithmetic operation (e.g., adding a string to an integer). Option D returns a string, so subsequent code expecting a number will fail. Options A, B, and C all return numeric types, so they would not cause that specific error.

Answer

value = eval(input("Enter a number: "))

Answer

value = float(input("Enter a number: "))

Answer

value = int(input("Enter a number: "))

Question 20

Which of the following is a valid Python variable name?

Accepted Answer

_var. (_var) is correct because in Python, variable names must start with a letter or an underscore, and can contain letters, digits, and underscores. The underscore is explicitly allowed as the first character, making _var a valid identifier.

Answer

2var

Answer

var name

Answer

var-name