R SparkR over用法及代碼示例

說明：

定義一個窗口列。

用法：

over(x, window)

## S4 method for signature 'Column,WindowSpec'
over(x, window)

參數：

• x 一列，通常由窗口函數返回。
• window 一個 WindowSpec 對象。可以由windowPartitionBy 或windowOrderBy 創建並由其他 WindowSpec 方法配置。

注意：

從 2.0.0 開始

例子：

df <- createDataFrame(mtcars)

  # Partition by am (transmission) and order by hp (horsepower)
  ws <- orderBy(windowPartitionBy("am"), "hp")

  # Rank on hp within each partition
  out <- select(df, over(rank(), ws), df$hp, df$am)

  # Lag mpg values by 1 row on the partition-and-ordered table
  out <- select(df, over(lead(df$mpg), ws), df$mpg, df$hp, df$am)