lir.transform.select_instances module

class lir.transform.select_instances.SelectInstances(select_element_fn: Callable[[int], bool])

Bases: Transformer

Select elements in a dataset from their indices.

Parameters:

select_element_fn (Callable[[int], bool]) – A function that takes a line number and returns True if it should be included, or False if it should be discarded.

Examples

This filter can be used in a YAML configuration:

data:
  provider: [...]
  strategy: [...]
  filter:
    method: select_instances # drop instances unless their indices matches any of the following patterns
    indices:
      - 2                    # select element 2 -- the third record
      - 0-99                 # select element 0-99 (inclusive) -- the first 100 records
      - 0-99,800-899         # select element 0-99 and 800-899
      - /5                   # select every fifth element: 0, 5, 10, ...

apply(instances: DataType) → DataType

Apply the selection to a dataset.

Parameters:

instances (InstanceData) – The dataset to select instances from.

Returns:

A dataset with only the selected instances.

Return type:

InstanceData