// 創建視圖 data.createOrReplaceTempView("Affairs") val df1 = spark.sql("SELECT * FROM Affairs WHERE age BETWEEN 20 AND 25") df1 ...
val dfList List Hadoop , Java,SQL,Hive,HBase,MySQL , Spark , Scala,SQL,DataSet,MLlib,GraphX dfList: List String, String List Hadoop,Java,SQL,Hive,HBase,MySQL , Spark,Scala,SQL,DataSet,MLlib,GraphX ca ...
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// 創建視圖 data.createOrReplaceTempView("Affairs") val df1 = spark.sql("SELECT * FROM Affairs WHERE age BETWEEN 20 AND 25") df1 ...
data.groupBy("gender").agg(count($"age"),max($"age").as("maxAge"), avg($"age").as("avgAge")).show ...
import org.apache.spark.sql.functions._ // 對整個DataFrame的數據去重 data.distinct() data.dropDuplicates() // 對指定列的去重 val colArray=Array ...
import org.apache.spark.storage.StorageLevel // 數據持久緩存到內存中//data.cache()data.persist() // 設置緩存級別data.persist(StorageLevel.DISK_ONLY) // 清除緩存 ...
Affairs group by gender // 創建視圖 data.createO ...
val df6 = spark.sql("select gender,children,max(age),avg(age),count(age) from Affairs group by Cube(gender,children) order by 1,2") df6.show +------+--------+--------+--------+----------+ ...
import org.apache.spark.sql.SparkSession import org.apache.spark.sql.Dataset import org.apache.spark.sql.Row import ...
Dataset是一個強類型的特定領域的對象,這種對象可以函數式或者關系操作並行地轉換。每個Dataset也有一個被稱為一個DataFrame的類型化視圖,這種DataFrame是Row類型的Dataset,即Dataset[Row] Dataset是“懶惰”的,只在執行行動操作時觸發計算 ...