PySpark enumerate in partition under condition

Question

I have a pySpark dataFrame like:

class   classID Property
1       1       1
1       2       0
1       3       1
1       4       1
2       1       0   
2       2       0
2       3       1

Now I need to add a column with the information how many rows within the current partition until this row do have the Property == 1. Like here:

class   classID Property    relevantCount
1       1       1           1
1       2       0           1   
1       3       1           2
1       4       1           3
2       1       0           0   
2       2       0           0
2       3       1           1

E.g. I tried a Window function:

import pyspark.sql.functions as f
from pyspark.sql.window import Window
windowSpec = Window().partitionBy('class').orderBy(f.col('classID'))
df = df \
.withColumn('relevantCount',(f.when((f.col('rank') == f.lit(1)) & (f.col('Property') == f.lit(0)),0)).otherwise(f.col('Property')+f.col(f.lag('deliveryCountDesc').over(windowSpec))))

But I can not reference on the previous values of the new line.

Does anyone have a better idea?

Manoj Singh Manoj Singh · Accepted Answer · 2018-12-04T16:31:57

Your window spec needs to be modified to include all previous rows in the partition and take the count with matching property values. Try this

import pyspark.sql.functions as f
from pyspark.sql.window import Window
data = [(1, 1,1),(1, 2,0),(1, 3,1),(1, 4,1),(2,1 , 0),(2, 2, 0),(2, 3, 1)]
df = spark.createDataFrame(data,['class','classID','Property'])
windowSpec = Window().partitionBy('class').orderBy('classID').rowsBetween(Window.unboundedPreceding, Window.currentRow)
df = df.withColumn('relevantCount',f.count(f.when(f.col('Property') == 1, f.col('Property'))).over(windowSpec))
df.show()

Result >

+-----+-------+--------+-------------+
|class|classID|Property|relevantCount|
+-----+-------+--------+-------------+
|    1|      1|       1|            1|
|    1|      2|       0|            1|
|    1|      3|       1|            2|
|    1|      4|       1|            3|
|    2|      1|       0|            0|
|    2|      2|       0|            0|
|    2|      3|       1|            1|
+-----+-------+--------+-------------+

PySpark enumerate in partition under condition

1 Answers