如何在PySpark中在一天内累积超过1小时的窗口 [英] How to aggregate over '1 hour' windows cumulatively within a day in PySpark

问题描述

我有一个Spark DataFrame，如下所示:

I have a Spark DataFrame like the one below:

+---------+--------------------------+
|group_id |event_time                |
+---------+--------------------------+
|XXXX     |2017-10-25 14:47:02.717013|
|XXXX     |2017-10-25 14:47:25.444979|
|XXXX     |2017-10-25 14:49:32.21353 |
|YYYY     |2017-10-25 14:50:38.321134|
|YYYY     |2017-10-25 14:51:12.028447|
|ZZZZ     |2017-10-25 14:51:24.810688|
|YYYY     |2017-10-25 14:37:34.241097|
|ZZZZ     |2017-10-25 14:37:24.427836|
|XXXX     |2017-10-25 14:37:24.620864|
|YYYY     |2017-10-25 14:37:24.964614|
+---------+--------------------------+

我想计算每个 group_id 在一天之内每小时发生的事件的滚动计数.

I want to calculate the rolling count of events per hour within a day per group_id.

因此，对于日期时间 25-10 14:00 和 group_id ，我想计算该 group_id 从 25-10 00:00 到 25-10 14:00 .

So, for the datetime 25-10 14:00 and for a group_id, I want to calculate the count of events for that group_id from 25-10 00:00 till 25-10 14:00.

执行以下操作:

df.groupBy('group_id', window('event_time', '1 hour').alias('model_window')) \
    .agg(dfcount(lit(1)).alias('values'))

计算每小时的事件计数，但不是每天的累积计数.

calculates the count of events per hour, but not cumulatively during each day.

有什么想法吗?

编辑:预期的输出将类似于:

EDIT: The expected output would be something like:

    +---------+---------------------------------------------+-------+
    |group_id |model_window                                 |values |         
    +---------+---------------------------------------------+-------+
    |XXXX     |[2017-10-25 00:00:00.0,2017-10-25 01:00:00.0]| 10    |
    |XXXX     |[2017-10-25 00:00:00.0,2017-10-25 02:00:00.0]| 17    |
    |XXXX     |[2017-10-25 00:00:00.0,2017-10-25 03:00:00.0]| 22    |
    |YYYY     |[2017-10-25 00:00:00.0,2017-10-25 01:00:00.0]| 0     |
    |YYYY     |[2017-10-25 00:00:00.0,2017-10-25 02:00:00.0]| 1     |
    |YYYY     |[2017-10-25 00:00:00.0,2017-10-25 03:00:00.0]| 9     |
    +---------+---------------------------------------------+-------+

推荐答案

想在一天之内每个group_id每小时计算....

want to calculate ... per hour within a day per group_id.

提取数据和小时:

from pyspark.sql.functions import col, count, hour, sum

extended = (df
  .withColumn("event_time", col("event_time").cast("timestamp"))
  .withColumn("date", col("event_time").cast("date"))
  .withColumn("hour", hour(col("event_time"))))

计算聚合

aggs = extended.groupBy("group_id", "date", "hour").count()

我要计算事件的滚动计数

I want to calculate the rolling count of events

并使用窗口功能:

from pyspark.sql.window import Window

aggs.withColumn(
    "agg_count", 
    sum("count").over(Window.partitionBy("group_id", "date").orderBy("hour")))

要在缺少时间间隔的情况下获得0，您必须为每个日期和小时生成参考数据并将其加入.

To get 0 for missing intervals you'll have to generate reference data for each date and hour and join it.

将 df 定义为:

df = sc.parallelize([
    ("XXXX", "2017-10-25 01:47:02.717013"),
    ("XXXX", "2017-10-25 14:47:25.444979"),
    ("XXXX", "2017-10-25 14:49:32.21353"),
    ("YYYY", "2017-10-25 14:50:38.321134"),
    ("YYYY", "2017-10-25 14:51:12.028447"),
    ("ZZZZ", "2017-10-25 14:51:24.810688"),
    ("YYYY", "2017-10-25 14:37:34.241097"),
    ("ZZZZ", "2017-10-25 14:37:24.427836"),
    ("XXXX", "2017-10-25 22:37:24.620864"),
    ("YYYY", "2017-10-25 16:37:24.964614")
]).toDF(["group_id", "event_time"])

结果是

+--------+----------+----+-----+---------+                                      
|group_id|      date|hour|count|agg_count|
+--------+----------+----+-----+---------+
|    XXXX|2017-10-25|   1|    1|        1|
|    XXXX|2017-10-25|  14|    2|        3|
|    XXXX|2017-10-25|  22|    1|        4|
|    ZZZZ|2017-10-25|  14|    2|        2|
|    YYYY|2017-10-25|  14|    3|        3|
|    YYYY|2017-10-25|  16|    1|        4|
+--------+----------+----+-----+---------+

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