featurebyte.EventViewColumn.lag

lag(

entity_columns: Union[str, List[str]],

offset: int=1

) -> LagColumnTypeT

Description

Lag is a transform that enables the retrieval of the preceding value associated with a particular entity in a view.

This makes it feasible to compute essential features, such as those that depend on inter-event time and the proximity to the previous point.

Parameters

• entity_columns: Union[str, List[str]]
  Entity columns used when retrieving the lag value.
  
  
• offset: int
  default: 1
  The number of rows backward from which to retrieve a value.
  
  

Returns

• LagColumnTypeT
  
  

Raises

• ValueError
  If a lag operation has already been applied to the column.
  
  

Examples

Create a new column that indicates the prior event timestamp for a Customer.

>>> event_view = catalog.get_view("GROCERYINVOICE")
>>> lagged_column = event_view["Timestamp"].lag("GroceryCustomerGuid")

Create a new column that indicates the 2nd prior event timestamp for a Customer.

>>> lagged_2_column = event_view["Timestamp"].lag(
...   "GroceryCustomerGuid", offset=2
... )