Data Transformation interview questions

15 real Data Transformation questions from the Functional Programming bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.

1. What is Map?

Junior
  1. A.a routine that returns a boolean indicating whether its input meets some condition
  2. B.applying a routine to every element of a collection to produce a new collection of the same length
  3. C.collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
  4. D.the general operation that walks a structure carrying an accumulator, of which left and right variants differ in association order
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3. Which statement is correct?

Junior
  1. A.Map — a routine that returns a boolean indicating whether its input meets some condition
  2. B.Map — applying a routine to every element of a collection to produce a new collection of the same length
  3. C.Map — collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
  4. D.Map — selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
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4. What is Filter?

Junior
  1. A.selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
  2. B.collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
  3. C.applying a routine to every element of a collection to produce a new collection of the same length
  4. D.the general operation that walks a structure carrying an accumulator, of which left and right variants differ in association order
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6. Which statement is correct?

Junior
  1. A.Filter — collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
  2. B.Filter — selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
  3. C.Filter — applying a routine to every element of a collection to produce a new collection of the same length
  4. D.Filter — a routine that returns a boolean indicating whether its input meets some condition
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7. What is Reduce?

Mid
  1. A.applying a routine to every element of a collection to produce a new collection of the same length
  2. B.selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
  3. C.a routine that returns a boolean indicating whether its input meets some condition
  4. D.collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
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9. Which statement is correct?

Mid
  1. A.Reduce — applying a routine to every element of a collection to produce a new collection of the same length
  2. B.Reduce — the general operation that walks a structure carrying an accumulator, of which left and right variants differ in association order
  3. C.Reduce — selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
  4. D.Reduce — collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
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10. What is Fold?

Mid
  1. A.collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
  2. B.selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
  3. C.the general operation that walks a structure carrying an accumulator, of which left and right variants differ in association order
  4. D.a routine that returns a boolean indicating whether its input meets some condition
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12. Which statement is correct?

Mid
  1. A.Fold — selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
  2. B.Fold — the general operation that walks a structure carrying an accumulator, of which left and right variants differ in association order
  3. C.Fold — a routine that returns a boolean indicating whether its input meets some condition
  4. D.Fold — collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
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13. What is Predicate?

Junior
  1. A.the general operation that walks a structure carrying an accumulator, of which left and right variants differ in association order
  2. B.a routine that returns a boolean indicating whether its input meets some condition
  3. C.selecting the elements of a collection that satisfy a predicate to produce a shorter new collection
  4. D.collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
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15. Which statement is correct?

Junior
  1. A.Predicate — collapsing a collection into a single accumulated value by repeatedly combining elements with an accumulator
  2. B.Predicate — a routine that returns a boolean indicating whether its input meets some condition
  3. C.Predicate — applying a routine to every element of a collection to produce a new collection of the same length
  4. D.Predicate — the general operation that walks a structure carrying an accumulator, of which left and right variants differ in association order
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