A data analyst needs to process a list of sensor readings that may contain None values. They want to compute the average of the non-None values. Which code snippet is most robust and Pythonic?

avg = sum([x for x in readings if x]) / len([x for x in readings if x])

avg = sum(filter(None, readings)) / len(readings)

valid = [x for x in readings if x is not None]; avg = sum(valid) / len(valid)

avg = sum(readings) / len(readings)

A financial analyst writes a Python function to calculate the average of a list of numbers. They want the function to be reusable and avoid modifying the original list. Which function definition best follows best practices?

def average(numbers): return sum(numbers) / len(numbers)

def average(numbers): total = 0; for n in numbers: total += n; return total / len(numbers)

def average(numbers): return sum(numbers) // len(numbers)

def average(numbers): numbers.append(sum(numbers)/len(numbers)); return numbers[-1]

A data team is establishing coding standards for their Python data analysis projects. Which of the following practices are considered best practices? Select all that apply.

Document functions with docstrings.

Write unit tests for data processing functions.

Avoid using version control for notebooks.

Use virtual environments to manage dependencies.

Use global variables to share data across modules.

A data analyst needs to filter a list of customer records (stored as dictionaries) to keep only those with age >= 18 and country == 'USA'. They want to write clean, efficient code. Which approach is best?

Use the filter() function with a lambda: list(filter(lambda r: r['age'] >= 18 and r['country'] == 'USA', records))

Use a for loop that appends matching records to a new list.

Use a list comprehension with an if condition: [r for r in records if r['age'] >= 18 and r['country'] == 'USA']

Use a set comprehension to filter the records.

Python InstitutePCAD - Certified Associate in Data Analytics with Python

Domain 2Objective 1

Core Python Proficiency PCAD-31 Practice Questions (Page 5)

Part of the Programming and Database Skills domain, which accounts for 33.3% of the PCAD-31 exam. Python Institute does not publish an official question count, but from its 60-minute exam (~25–40 total, ~8–8 in this domain), expect 2–2 from this objective — we provide 50 practice questions to prepare you well beyond it. (estimate)

50questions here

10free pages

5concepts

33.3%of the exam

Questions 21–25

21expert · hard
A data analyst needs to process a list of sensor readings that may contain None values. They want to compute the average of the non-None values. Which code snippet is most robust and Pythonic?
Select an answer first
22application · medium
A financial analyst writes a Python function to calculate the average of a list of numbers. They want the function to be reusable and avoid modifying the original list. Which function definition best follows best practices?
Select an answer first
23expert · hard · select all that apply
A data team is establishing coding standards for their Python data analysis projects. Which of the following practices are considered best practices? Select all that apply.
Select an answer first
24application · easy
A data scientist is working in a Jupyter notebook and needs to load a CSV file into a tabular structure for analysis. They want to use the most appropriate library for this task. Which library should they use?
Select an answer first
25application · medium
A data analyst needs to filter a list of customer records (stored as dictionaries) to keep only those with age >= 18 and country == 'USA'. They want to write clean, efficient code. Which approach is best?
Select an answer first

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