lenskit.splitting.LastFrac

class lenskit.splitting.LastFrac(frac, field='timestamp')

Bases: HoldoutMethod

Select a fraction of test rows per user/item.

Stability:

Caller (see Stability Levels).

Parameters:

• frac (double) – the fraction of items to select for testing.

• field (str)

fraction: float

field: str

__call__(items)

Subset an item list (in the uncommon case of item-based holdouts, the item list actually holds user IDs).

Parameters:

• udf – The item list from which holdout items should be selected.

• items (lenskit.data.ItemList)

Returns:

The list of test items.

Return type:

lenskit.data.ItemList