Describe the Use of Lists, Dictionaries, Tuples, Sets, and Strings DATA-ENGINEERING-OPTIMIZE Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   Given the list `data = [10, 20, 30, 40]`, what is the result of `data[2]`?

   • A30
   • B20
   • C40
   • DAn IndexError
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2. 2expert · medium

   A data engineer has a string `s = '2025-03-14,ERROR,disk full'` and needs to extract the error message 'disk full' and convert it to uppercase. Which expression accomplishes this?

   • As.split(',')[2].upper()
   • Bs[2:].upper()
   • Cs.split(',')[1].upper()
   • Ds.replace(',', ' ').upper()
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4. 3expert · hard

   A data pipeline maintains a list of recently processed file paths. The list is used to display the last 10 files in order, and it is updated frequently by adding new paths at the end and removing the oldest path when the list exceeds 10. The engineer also needs to check whether a specific file path has been processed recently. Which data structure is the most appropriate?

   • AA set, using `add` and `discard` to manage entries
   • BA dictionary, using file paths as keys and timestamps as values
   • CA tuple, using concatenation to add and slicing to remove the oldest
   • DA list, using `append` to add and `pop(0)` to remove the oldest
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5. 4foundation · easy

   What is the result of `{1, 2, 3} | {3, 4, 5}`?

   • A{1, 2, 4, 5}
   • B{1, 2, 3, 4, 5}
   • C{3}
   • D{1, 2, 3, 3, 4, 5}
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6. 5application · medium

   A data engineer has two lists of customer IDs: one from the marketing system and one from the sales system. The engineer needs to find all customer IDs that appear in BOTH systems to identify customers who are both marketed to and have made a purchase. Which approach is the most efficient?

   • AConvert both lists to sets and use the intersection operator `&`
   • BUse a nested loop to compare each ID in the first list with each ID in the second list
   • CAppend all IDs from both lists to a single list and remove duplicates
   • DCreate a dictionary from the first list and check membership in the second list
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