# DocSplitFilter **`class DocSplitFilter(config)`** Bases: [`Filter`](squirro.lib.nlp.steps.filters.Filter.md#squirro.lib.nlp.steps.filters.Filter) The doc_split [`Filter`](squirro.lib.nlp.steps.filters.Filter.md#squirro.lib.nlp.steps.filters.Filter) splits a single [`Document`](../technical/libnlp/base.md#squirro.lib.nlp.document.Document) into many via iterable fields of the same length. **Input** - all input fields need to be of type [`list`](https://docs.python.org/3.11/library/stdtypes.html#list) [ [`object`](https://docs.python.org/3.11/library/functions.html#object) ]. **Output** - The output fields are going to be of type [`object`](https://docs.python.org/3.11/library/functions.html#object). Parameters - `type` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)) – doc_split - `fields` ([`list`](https://docs.python.org/3.11/library/stdtypes.html#list)) – Fields to split on (must all be same length) - `flatten` ([`bool`](https://docs.python.org/3.11/library/functions.html#bool)`, ``False`) – Whether or not to flatten the split fields - `copy_fields` ([`bool`](https://docs.python.org/3.11/library/functions.html#bool)`, ``False`) – Whether to refer or copy the other fields of the document to the new generated documents. If you expect to mutate the other fields of the generated document in subsequent steps, then set this parameter to true. However, please note that this may come with a performance penalty when the document has many number of elements for the defined fields. **Example** ```json { "step": "filter", "type": "doc_split", "fields":["sentences"] } ``` Methods SummaryMethods Documentation **`process(docs)`** Process a set of documents Parameters `docs` (`generator``(`[`Document`](../technical/libnlp/base.md#squirro.lib.nlp.document.Document)`)`) – Generator of documents Returns Generator of processed documents Return type generator([Document](../technical/libnlp/base.md#squirro.lib.nlp.document.Document)) **`train(docs)`** Train on a step of a set of documents Parameters `docs` (`generator``(`[`Document`](../technical/libnlp/base.md#squirro.lib.nlp.document.Document)`)`) – Generator of documents Returns Generator of processed documents Return type generator([Document](../technical/libnlp/base.md#squirro.lib.nlp.document.Document))