Scala Collections and RDD Operations
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Questions and Answers

Which type of loop guarantees that the code inside will execute at least once?

  • foreach loop
  • do-while loop (correct)
  • for loop
  • while loop

    • What will the sumSquares function compute when called with arguments 1 and 3?

  • 14 (correct)
  • 6
  • 9
  • 2

    • What is a key feature of immutable collections in Scala?

  • They are faster than mutable collections.
  • They can be modified in place.
  • They allow for updates without creating a new collection.
  • They cannot be changed after their creation. (correct)

    • What is a characteristic of arrays in Scala?

    <p>They are a fixed-size sequential collection.</p> Signup and view all the answers

    Which of the following correctly defines a list in Scala?

    <p>val l = 1 :: 2 :: 3 :: Nil</p> Signup and view all the answers

    What happens when you try to add an element to a list in Scala?

    <p>A new list is created with the element added.</p> Signup and view all the answers

    Which statement about sets in Scala is true?

    <p>Sets can be immutable and mutable.</p> Signup and view all the answers

    How do you access an element in an array in Scala?

    <p>By its index within parentheses.</p> Signup and view all the answers

    What is the primary difference between arrays and lists in Scala?

    <p>Arrays are mutable, while lists are immutable.</p> Signup and view all the answers

    Which operation allows you to add an element to the head of a list in Scala?

    <p>0 :: l1</p> Signup and view all the answers

    In Scala, which of the following is NOT a collection type?

    <p>Tuple</p> Signup and view all the answers

    What type of operation do transformations in RDDs represent?

    <p>Creation of a new RDD from an existing one</p> Signup and view all the answers

    Which of the following best describes the behavior of transformations in RDDs?

    <p>They are executed when an action is invoked</p> Signup and view all the answers

    What does the map transformation do in the context of RDDs?

    <p>Applies a function to each record independently</p> Signup and view all the answers

    In the context of key-value RDD transformations, what does 'k' represent?

    <p>The key associated with a value in the RDD</p> Signup and view all the answers

    What is the purpose of the filter transformation in an RDD?

    <p>To remove elements that do not meet a certain condition</p> Signup and view all the answers

    What is meant by 'lineage' in the context of RDD transformations?

    <p>The sequence of transformations used to create an RDD</p> Signup and view all the answers

    What is the result of using the reduce operation on an RDD?

    <p>It combines the elements of the RDD into a single value</p> Signup and view all the answers

    Which function is commonly associated with aggregating values in key-value RDDs?

    <p>addFunc</p> Signup and view all the answers

    Study Notes

    Scala Collections

    • Scala collections can be mutable or immutable.
    • Mutable collections can be updated or extended in place.
    • Immutable collections never change; additions, removals, or updates operators return a new collection and leave the old collection unchanged.

    RDD Operations

    • There are two types of operations:
      • Transformations: used to build the logical plan for an RDD
      • Actions: trigger the computation of an RDD

    Transformations

    • Transformations create a new RDD from an existing one.
    • All transformations are lazy, meaning they do not compute their results immediately.
    • Transformations are only computed when an action requires a result to be returned to the driver program.

    Generic RDD Transformations

    • The map transformation applies a given function to each RDD record independently.

    Lineage

    • Lineage refers to the chain of transformations used to build an RDD.
    • RDDs are stored as a chain of objects capturing the lineage of each RDD.

    Key-Value RDD Transformations

    • Key-value RDDs are pairs, where k is the key and v is the value.
    • To create a key-value RDD, simply map over the current RDD to create a basic key-value structure.

    Key-Value RDD Transformations - Aggregation

    • The aggregateByKey method aggregates the values associated with each key.
    • To use the aggregateByKey method, define a function that sums up the values for each key.

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    Related Documents

    ID2221.pdf

    Description

    Explore the fundamental concepts of Scala collections, including mutable and immutable types. Dive into RDD operations with a focus on transformations and actions, and understand the importance of lineage in managing RDDs.

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