# Extract Strings

### Description
Extracts string values from an object for a specific property.
For example, it can be used to extract the title from a document, or the name of a person.
The property should be provided as a parameter. With additional blocks, the extracted values can be transformed or used in a retrieval model.

### Input
- `SOURCE [OBJ]`: a list of objects

### Output
- `PAIR [OBJ,STRING]`: for each object in the input source the extracted string value is provided as the second column in `[OBJ,STRING]`. When multiple values can be extracted for an object, each object-value pair is returned as a separate result.
- `RESULT [STRING]`: the extracted values, disjoint from their parent object. Use the score aggregation parameter to define how occurrences of the same value are handled.

### Parameters
- `Property`: the property to extract the values from. Use `*` to extract values from all properties
- `Use sub-properties`: when set to `true`, the values of all sub properties are also included. Sub-properties can be defined in the data with the `rdfs:subPropertyOf` relation.
- `Language`: when a language is selected, only the strings in this language are extracted. This uses the language tags that are defined in the data.

Output scores can be [aggregated](docs://score_aggregation) and/or [normalised](docs://score_normalisation).