OpenSearch/docs/reference/analysis/analyzers/stop-analyzer.asciidoc

[[analysis-stop-analyzer]]
=== Stop Analyzer

The `stop` analyzer is the same as the <<analysis-simple-analyzer,`simple` analyzer>>
but adds support for removing stop words.  It defaults to using the
`_english_` stop words.

[float]
=== Example output

[source,console]
---------------------------
POST _analyze
{
  "analyzer": "stop",
  "text": "The 2 QUICK Brown-Foxes jumped over the lazy dog's bone."
}
---------------------------

/////////////////////

[source,console-result]
----------------------------
{
  "tokens": [
    {
      "token": "quick",
      "start_offset": 6,
      "end_offset": 11,
      "type": "word",
      "position": 1
    },
    {
      "token": "brown",
      "start_offset": 12,
      "end_offset": 17,
      "type": "word",
      "position": 2
    },
    {
      "token": "foxes",
      "start_offset": 18,
      "end_offset": 23,
      "type": "word",
      "position": 3
    },
    {
      "token": "jumped",
      "start_offset": 24,
      "end_offset": 30,
      "type": "word",
      "position": 4
    },
    {
      "token": "over",
      "start_offset": 31,
      "end_offset": 35,
      "type": "word",
      "position": 5
    },
    {
      "token": "lazy",
      "start_offset": 40,
      "end_offset": 44,
      "type": "word",
      "position": 7
    },
    {
      "token": "dog",
      "start_offset": 45,
      "end_offset": 48,
      "type": "word",
      "position": 8
    },
    {
      "token": "s",
      "start_offset": 49,
      "end_offset": 50,
      "type": "word",
      "position": 9
    },
    {
      "token": "bone",
      "start_offset": 51,
      "end_offset": 55,
      "type": "word",
      "position": 10
    }
  ]
}
----------------------------

/////////////////////


The above sentence would produce the following terms:

[source,text]
---------------------------
[ quick, brown, foxes, jumped, over, lazy, dog, s, bone ]
---------------------------

[float]
=== Configuration

The `stop` analyzer accepts the following parameters:

[horizontal]
`stopwords`::

    A pre-defined stop words list like `_english_` or an array  containing a
    list of stop words.  Defaults to `_english_`.

`stopwords_path`::

    The path to a file containing stop words. This path is relative to the
    Elasticsearch `config` directory.


See the <<analysis-stop-tokenfilter,Stop Token Filter>> for more information
about stop word configuration.

[float]
=== Example configuration

In this example, we configure the `stop` analyzer to use a specified list of
words as stop words:

[source,console]
----------------------------
PUT my_index
{
  "settings": {
    "analysis": {
      "analyzer": {
        "my_stop_analyzer": {
          "type": "stop",
          "stopwords": ["the", "over"]
        }
      }
    }
  }
}

POST my_index/_analyze
{
  "analyzer": "my_stop_analyzer",
  "text": "The 2 QUICK Brown-Foxes jumped over the lazy dog's bone."
}
----------------------------

/////////////////////

[source,console-result]
----------------------------
{
  "tokens": [
    {
      "token": "quick",
      "start_offset": 6,
      "end_offset": 11,
      "type": "word",
      "position": 1
    },
    {
      "token": "brown",
      "start_offset": 12,
      "end_offset": 17,
      "type": "word",
      "position": 2
    },
    {
      "token": "foxes",
      "start_offset": 18,
      "end_offset": 23,
      "type": "word",
      "position": 3
    },
    {
      "token": "jumped",
      "start_offset": 24,
      "end_offset": 30,
      "type": "word",
      "position": 4
    },
    {
      "token": "lazy",
      "start_offset": 40,
      "end_offset": 44,
      "type": "word",
      "position": 7
    },
    {
      "token": "dog",
      "start_offset": 45,
      "end_offset": 48,
      "type": "word",
      "position": 8
    },
    {
      "token": "s",
      "start_offset": 49,
      "end_offset": 50,
      "type": "word",
      "position": 9
    },
    {
      "token": "bone",
      "start_offset": 51,
      "end_offset": 55,
      "type": "word",
      "position": 10
    }
  ]
}
----------------------------

/////////////////////


The above example produces the following terms:

[source,text]
---------------------------
[ quick, brown, foxes, jumped, lazy, dog, s, bone ]
---------------------------

[float]
=== Definition

It consists of:

Tokenizer::
* <<analysis-lowercase-tokenizer,Lower Case Tokenizer>>

Token filters::
* <<analysis-stop-tokenfilter,Stop Token Filter>>

If you need to customize the `stop` analyzer beyond the configuration
parameters then you need to recreate it as a `custom` analyzer and modify
it, usually by adding token filters. This would recreate the built-in
`stop` analyzer and you can use it as a starting point for further
customization:

[source,console]
----------------------------------------------------
PUT /stop_example
{
  "settings": {
    "analysis": {
      "filter": {
        "english_stop": {
          "type":       "stop",
          "stopwords":  "_english_" <1>
        }
      },
      "analyzer": {
        "rebuilt_stop": {
          "tokenizer": "lowercase",
          "filter": [
            "english_stop"          <2>
          ]
        }
      }
    }
  }
}
----------------------------------------------------
// TEST[s/\n$/\nstartyaml\n  - compare_analyzers: {index: stop_example, first: stop, second: rebuilt_stop}\nendyaml\n/]

<1> The default stopwords can be overridden with the `stopwords`
    or `stopwords_path` parameters.
<2> You'd add any token filters after `english_stop`.