Coverage for jstark / features / recency_days.py: 100%

1"""RecencyDays feature""" 

2 

3import pyspark.sql.functions as f 

4from pyspark.sql import Column 

5 

6from jstark.features.min_feature import Min 

7 

8 

9class RecencyDays(Min): 

10 def column_expression(self) -> Column: 

11 return f.datediff(f.lit(self.as_at), f.col("Timestamp")) 

12 

13 def default_value(self) -> Column: 

14 return f.lit(0) 

15 

16 @property 

17 def description_subject(self) -> str: 

18 return "Minimum number of days since occurrence" 

19 

20 @property 

21 def commentary(self) -> str: 

22 return ( 

23 "This could be particularly useful (for example) in a grocery retailer " 

24 + "for determining when a customer most recently bought a product or " 

25 + " when a product was most recently bought in a store" 

26 + "Also note that this is very similar to " 

27 + f"MostRecentPurchaseDate_{self.feature_period.mnemonic} " 

28 + "so consider which of these " 

29 + "features is most useful to you." 

30 )