如何计算spark中DataFrame中列的百分比? [英] How to calculate Percentile of column in a DataFrame in spark?

问题描述

我想计算 DataFrame 中某一列的百分位数?我在 Spark 聚合函数中找不到任何 percentile_approx 函数.

I am trying to calculate percentile of a column in a DataFrame? I cant find any percentile_approx function in Spark aggregation functions.

例如在 Hive 中，我们有 percentile_approx，我们可以通过以下方式使用它

For e.g. in Hive we have percentile_approx and we can use it in the following way

hiveContext.sql("select percentile_approx("Open_Rate",0.10) from myTable); 

但出于性能原因，我想使用 Spark DataFrame 来实现.

But I want to do it using Spark DataFrame for performance reasons.

样本数据集

|User ID|Open_Rate|
------------------- 
|A1     |10.3     |
|B1     |4.04     |
|C1     |21.7     |
|D1     |18.6     |

我想知道有多少用户属于 10% 或 20% 等等.我想做这样的事情

I want to find out how many users fall into 10 percentile or 20 percentile and so on. I want to do something like this

df.select($"id",Percentile($"Open_Rate",0.1)).show

推荐答案

自从 Spark2.0 以来，事情变得越来越容易，只需在 DataFrameStatFunctions 中使用此函数，例如:

Since Spark2.0, things are getting easier,simply use this function in DataFrameStatFunctions like :

df.stat.approxQuantile("Open_Rate",Array(0.25,0.50,0.75),0.0)

DataFrameStatFunctions 中还有一些有用的 DataFrame 统计函数.

There are also some useful statistic functions for DataFrame in DataFrameStatFunctions.

这篇关于如何计算spark中DataFrame中列的百分比?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！