featurebyte.ChangeViewColumn.lag

lag(

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

offset: int=1

) -> ChangeViewColumn

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

• ChangeViewColumn
  
  

Raises

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

Examples

Get a ChangeView to track changes in Customer's State.

>>> scd_table = catalog.get_table("GROCERYCUSTOMER")
>>> change_view = scd_table.get_change_view(
...   track_changes_column="State"
... )

Create a new column that indicates the prior past_State for a Customer

>>> lagged_column = change_view["past_State"].lag("GroceryCustomerGuid")