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 (D)</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. (B)</p> Signup and view all the answers

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

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

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

<p>Cluster nodes (B)</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 (A)</p> Signup and view all the answers

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

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

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

<p>Cluster mode (D)</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 (B)</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) (C)</p> Signup and view all the answers

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

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

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

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

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

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

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

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

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