Data Filters (filter)ΒΆ

Instances of classes derived from Filter are used for filtering the data.

When called with an individual data instance (, they accept or reject the instance by returning either True or False.

When called with a data storage (e.g. an instance of they check whether the corresponding class provides the method that implements the particular filter. If so, the method is called and the result should be of the same type as the storage; e.g., filter methods of return new instances of, and filter methods of SQL proxies return new SQL proxies.

If the class corresponding to the storage does not implement a particular filter, the fallback computes the indices of the rows to be selected and returns data[indices].