如何计算DataFrame列的2的幂(How to calculate the power of 2 for the column of DataFrame)

如何计算DataFrame列的2的幂(How to calculate the power of 2 for the column of DataFrame)

我需要使用Spark 2.2和Scala计算列p的2的幂：

但如果我这样做，我得到错误，因为($"ki" / $"ni")是列，而不是Double。

df.withColumn("p",(lit(1) - scala.math.pow(($"ki" / $"ni").as[Double],2))

I need to calculate the power of 2 for the column p using Spark 2.2 and Scala:

But if I do it this way, I get the error, because ($"ki" / $"ni") is the column, not Double.

df.withColumn("p",(lit(1) - scala.math.pow(($"ki" / $"ni").as[Double],2))

最满意答案

你可以使用内置的pow功能

import org.apache.spark.sql.functions._ df.withColumn("power_of_two", pow($"p", lit(2)))

you can use inbuilt pow function as

import org.apache.spark.sql.functions._ df.withColumn("power_of_two", pow($"p", lit(2)))