Missing Code Block Elements in Spark DataFrame
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Questions and Answers

What is the correct object to fill in gap 2 in the code block?

  • pyspark
  • DataFrame
  • len
  • spark (correct)

    • Which option correctly fills gap 3 in the code block?

  • DataFrameReader (correct)
  • pyspark
  • read()
  • spark

    • What is the correct parameter to fill in gap 4 in the code block?

  • size
  • escape='#'
  • comment='#' (correct)
  • shape

    • Which object should be used to evaluate the number of columns?

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

    Why can option B be eliminated as a correct answer?

    <p>DataFrame and shape are not compatible for evaluation.</p> Signup and view all the answers

    Which option provides an incorrect parameter value for reading a CSV file?

    <p>'shape'</p> Signup and view all the answers

    What is the role of the cluster manager in client mode?

    <p>Allocating resources to Spark applications and maintaining executor processes</p> Signup and view all the answers

    Where is the cluster manager located when operating in cluster mode?

    <p>Cluster nodes</p> Signup and view all the answers

    What action does the cluster manager take in remote mode?

    <p>Maintaining executor processes on the cluster nodes</p> Signup and view all the answers

    Which of the following is NOT a role of the cluster manager?

    <p>Managing the DataFrame operations</p> Signup and view all the answers

    In which mode does the cluster manager start and end executor processes?

    <p>Cluster mode</p> Signup and view all the answers

    What is the primary function of the cluster manager in Spark applications?

    <p>Allocating and managing cluster resources</p> Signup and view all the answers

    To perform an inner join between DataFrames transactionsDf and itemsDf on columns productId and itemId, which code block should be used?

    <p>transactionsDf.drop('value', 'storeId').join(itemsDf.select('attributes'), transactionsDf.productId==itemsDf.itemId)</p> Signup and view all the answers

    Which option correctly excludes columns 'value' and 'storeId' from DataFrame transactionsDf?

    <p>transactionsDf.drop('value', 'storeId')</p> Signup and view all the answers

    What is the purpose of using createOrReplaceTempView() in the context of DataFrames?

    <p>It creates a temporary view that can be used in SQL queries</p> Signup and view all the answers

    Which scenario would result in an incorrect inner join between two DataFrames?

    <p>Removing all columns from one of the DataFrames</p> Signup and view all the answers

    In the context of DataFrame joins, what does the 'ON' clause specify?

    <p>The condition for matching rows between DataFrames</p> Signup and view all the answers

    Which operation is NOT performed in the provided code block for joining DataFrames?

    <p>.drop('attributes')</p> Signup and view all the answers

    What method can be used to display the column names and types of a DataFrame in a tree-like structure?

    <p>itemsDf.rdd.printSchema()</p> Signup and view all the answers

    Which method can be used to change the data type of a column from integer to string in a DataFrame?

    <p>itemsDf.withColumn('itemId', convert('itemId', 'string'))</p> Signup and view all the answers

    Which method can be used to select all columns in a DataFrame with their corresponding data types?

    <p>print(itemsDf.columns)</p> Signup and view all the answers

    Which action is incorrect regarding the DataFrame's underlying RDD?

    <p>itemsDf.print.schema()</p> Signup and view all the answers

    What does the 'element: string (containsNull = true)' represent in the DataFrame's structure?

    <p>It signifies that the column 'element' contains nullable strings.</p> Signup and view all the answers

    What is the correct method to convert a column's data type in Spark from integer to string?

    <p>itemsDf.withColumn('itemId', col('itemId').cast('string'))</p> Signup and view all the answers

    What is the main requirement regarding the number of slots and tasks in Spark?

    <p>There is no specific requirement on the number of slots compared to tasks</p> Signup and view all the answers

    Why is having just a single slot for multiple tasks not recommended in Spark?

    <p>It prevents distributed data processing over multiple cores and machines</p> Signup and view all the answers

    Which of the following statements accurately represents the relationship between executors and tasks in Spark?

    <p>There is no specific requirement on the number of executors compared to tasks</p> Signup and view all the answers

    What does the code 'transactionsDf.groupBy('productId').agg(col('value').count())' achieve?

    <p>Groups by 'productId' but does not provide counts</p> Signup and view all the answers

    Why is calling 'transactionsDf.count('productId').distinct()' incorrect?

    <p>'count()' function does not take arguments in Spark</p> Signup and view all the answers

    Which DataFrame operation is necessary to get a 2-column DataFrame showing distinct 'productId' values and the number of rows with each 'productId'?

    <p>transactionsDf.groupBy('productId').count()</p> Signup and view all the answers

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