Collection.join#

Collection.join(
primary_keys: LazyFrame,
how: Literal['semi', 'anti'] = 'semi',
maintain_order: Literal['none', 'left'] = 'none',
) → Self[source]#

Filter the collection by joining onto a data frame containing entries for the common primary key columns whose respective rows should be kept or removed in the collection members.

Parameters:

  • primary_keys – The data frame to join on. Must contain the common primary key columns of the collection.

  • how – The join strategy to use. Like in polars, semi will keep all rows that can be found in primary_keys, anti will remove them.

  • maintain_order – The maintain_order option to use for the polars join.

Returns:

The collection, with members potentially reduced in length.

Raises:

ValueError – If the collection contains any member that is annotated with ignored_in_filters=True.

Attention

This method does not validate the resulting collection. Ensure to only use this if the resulting collection still satisfies the filters of the collection. The joins are not evaluated eagerly. Therefore, a downstream call to polars.LazyFrame.collect() may fail, especially if primary_keys does not contain all columns for all common primary keys.