In order to calculate cumulative sum of column in pyspark we will be using sum function and partitionBy. To calculate cumulative sum of a group in pyspark we will be using sum function and also we mention the group on which we want to partitionBy lets get clarity with an example.
Calculate cumulative sum of column in pyspark using sum() function
Calculate cumulative sum of the column by group in pyspark using sum() function and partitionby() function
cumulative sum of the column in pyspark with NaN / Missing values/ null values
We will use the dataframe named df_basket1.
Calculate Cumulative sum of column in pyspark
Sum() function and partitionBy() is used to calculate the cumulative sum of column in pyspark.
import sys
from pyspark.sql.window import Window
import pyspark.sql.functions as f
cum_sum = df_basket1.withColumn('cumsum', f.sum(df_basket1.Price).over(Window.partitionBy().orderBy().rowsBetween(-sys.maxsize, 0)))
cum_sum.show()
rowsBetween(-sys.maxsize, 0) along with sum function is used to create cumulative sum of the column and it is named as cumsum
Calculate Cumulative sum of the column by Group in pyspark
Sum() function and partitionBy a column name is used to calculate the cumulative sum of the “Price” column by group (“Item_group”) in pyspark
import sys
from pyspark.sql.window import Window
import pyspark.sql.functions as f
cum_sum = df_basket1.withColumn('cumsum', f.sum(df_basket1.Price).over(Window.partitionBy('Item_group').orderBy().rowsBetween(-sys.maxsize, 0)))
cum_sum.show()
rowsBetween(-sys.maxsize, 0) along with sum function is used to create cumulative sum of the column, an additional partitionBy() function of Item_group column calculates the cumulative sum of each group as shown below
Cumulative sum of the column with NA/ missing /null values
First lets look at a dataframe df_basket2 which has both null and NaN present which is shown below.
At First we will be replacing the missing and NaN values with 0, using fill.na(0) ; then will use Sum() function and partitionBy a column name is used to calculate the cumulative sum of the “Price” column
#### cumulative sum with NA and missing
import sys
from pyspark.sql.window import Window
import pyspark.sql.functions as f
df_basket2=df_basket2.fillna(0)
cum_sum = df_basket2.withColumn('cumsum', f.sum(df_basket2.Price).over(Window.partitionBy().orderBy().rowsBetween(-sys.maxsize, 0)))
cum_sum.show()
rowsBetween(-sys.maxsize, 0) along with sum function is used to create cumulative sum of the column as shown below
