DataFrame Transformations ASSOCIATE-DEVELOPER-APACHE-SPARK Practice Questions (Page 3)

Questions 11–15

1. 11foundation · easy

   Which two methods can be used interchangeably to filter rows in a DataFrame?

   • Afilter and where
   • Bdrop and filter
   • CorderBy and filter
   • Dselect and filter
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2. 12foundation · easy

   What is the difference between explode and explode_outer?

   • Aexplode_outer is faster than explode.
   • Bexplode_outer works on maps, while explode works on arrays.
   • Cexplode_outer returns an array, while explode returns rows.
   • Dexplode_outer produces a row with null for empty or null arrays, while explode does not.
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4. 13foundation · easy

   Which method collects all rows of a DataFrame to the driver as an Array[Row]?

   • Acollect
   • Btake
   • Cforeach
   • Dmap
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5. 14application · medium

   A DataFrame `transactions` has columns `txn_id`, `user_id`, `amount`, and `date`. Due to a data ingestion bug, some rows are exact duplicates. The team wants to remove duplicate rows based on all columns, then sort by `date` descending. Which code accomplishes this?

   • Atransactions.dropDuplicates().orderBy(col("date").desc())
   • Btransactions.distinct().orderBy("date")
   • Ctransactions.dropDuplicates(["txn_id", "user_id"]).orderBy(col("date").desc())
   • Dtransactions.dropDuplicates(["txn_id"]).orderBy(col("date").desc())
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6. 15foundation · easy

   What does the schema method return?

   • AAn array of column names
   • BA StructType object representing the schema
   • CA list of data types
   • DA string representation of the schema
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