CERTIFIED-DATA-ANALYST-ASSOCIATE · Question #5
A data engineer is working with a nested array column products in table transactions. They want to expand the table so each unique item in products for each row has its own row where the…
The correct answer is B. explode(produces). explode() is the correct function because it takes an array column and generates a new row for each element in the array, duplicating all other columns (like transaction_id) for each resulting row - exactly the "unnesting" behavior described. Why the distractors are wrong: A…
Question
A data engineer is working with a nested array column products in table transactions. They want to expand the table so each unique item in products for each row has its own row where the transaction_id column is duplicated as necessary. They are using the following incomplete command:
Which of the following line of code can they use to fill in the blank in the above code block so that it successfully completes the task?
Options
- Aarray distinct(produces)
- Bexplode(produces)
- Creduce(produces)
- Darray(produces)
- Eflatten(produces)
How the community answered
(27 responses)- A11% (3)
- B81% (22)
- C4% (1)
- D4% (1)
Explanation
explode() is the correct function because it takes an array column and generates a new row for each element in the array, duplicating all other columns (like transaction_id) for each resulting row - exactly the "unnesting" behavior described.
Why the distractors are wrong:
- A.
array_distinct()removes duplicate elements from an array but keeps the array as a single value - it doesn't expand rows. - C.
reduce()aggregates array elements into a single scalar value using a lambda function - the opposite of expanding. - D.
array()creates an array from individual values - it doesn't unpack one. - E.
flatten()collapses a nested array-of-arrays into a single array, but still returns one array per row, not individual rows.
Memory tip: Think of explode() literally - it "explodes" one row with an array into many rows, one per element. If you picture a row "blowing up" into multiple rows, that's your cue that explode() is the answer whenever a question asks about turning array elements into individual rows.
Community Discussion
No community discussion yet for this question.