Class `MatchScorer` allows you to sort documents based on the quality of query match. The scorer assigns a score based on term frequency in a document.

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To use a `MatchScorer`, add it to the `SortOptions` as in the following code:

```python
  sort_opts = search.SortOptions(match_scorer=search.MatchScorer())
```

This sorts the documents in descending score order. The scores will be
positive.

If you want to sort in ascending order, then use the following code:

```python
  sort_opts = search.SortOptions(match_scorer=search.MatchScorer(),
      expressions=[search.SortExpression(
          expression='_score', direction=search.SortExpression.ASCENDING,
          default_value=0.0)])
```

The scores in this case will be negative.

`MatchScorer` is defined in the `google.appengine.api.search` module.

## Constructor

The constructor for class `MatchScorer` is defined as follows:

class MatchScorer()

:   Assigns a document score to search results representing how well they match the query, base on frequency of terms in the document.

    Result value

    :   A new instance of class `MatchScorer`.

    Exceptions

    TypeError

    :   If any of the parameters have an invalid type, or an unknown attribute is passed.

    ValueError

    :   If any parameter has an invalid value.

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