A junior data analyst is writing a script to process sales data. They want to follow best practices for maintainability. Which practice should they adopt?

Avoid comments to keep the code short.

Use global variables to share data between parts of the script.

Break the script into small, well-named functions that each do one thing.

Write the entire script as a single block of code to avoid overhead.

A data analyst has a list of employee names and needs to remove duplicates while preserving the order of first occurrence. Which data structure and method should they use?

Use a dictionary with names as keys and values as None.

Use a set to track seen names and a list to build the unique list.

Use a tuple to store the names.

Convert the list to a set and then back to a list.

A data analyst is writing a function to clean a dataset. They want to pass a DataFrame to the function and have it return a cleaned DataFrame without modifying the original. Which function signature and body is best?

def clean_data(df): return df.dropna()

def clean_data(df): df = df.fillna(0); return df

def clean_data(df): df = df.dropna(); return df

def clean_data(df): df.dropna(inplace=True); return df

A data analyst needs to iterate over two lists of equal length (product names and prices) and print each pair. Which loop is most Pythonic?

for name, price in enumerate(names): print(name, price)

for name, price in zip(names, prices): print(name, price)

for name in names: print(name, prices[names.index(name)])

for i in range(len(names)): print(names[i], prices[i])

Python InstitutePCAD - Certified Associate in Data Analytics with Python

Domain 2Objective 1

Core Python Proficiency PCAD-31 Practice Questions (Page 6)

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 26–30

26application · medium
A junior data analyst is writing a script to process sales data. They want to follow best practices for maintainability. Which practice should they adopt?
Select an answer first
27application · medium
A data analyst has a list of employee names and needs to remove duplicates while preserving the order of first occurrence. Which data structure and method should they use?
Select an answer first
28application · medium
A data analyst is writing a function to clean a dataset. They want to pass a DataFrame to the function and have it return a cleaned DataFrame without modifying the original. Which function signature and body is best?
Select an answer first
29application · easy
A data scientist is working in a Jupyter notebook and needs to perform a complex numerical operation on a large array. They want to use vectorized operations for performance. Which library should they use?
Select an answer first
30application · easy
A data analyst needs to iterate over two lists of equal length (product names and prices) and print each pair. Which loop is most Pythonic?
Select an answer first

Finished these 5 questions?

Review the revealed explanations, or continue through the curriculum.

Next 5 questions →Back to PCAD-31

Free Basic Practice is a study aid with revealable answers — not a scored exam. Examers.io is independent and not affiliated with or endorsed by Python Institute. “PCAD-31” is a trademark of its owner, used for identification only.