[[analysis-stop-tokenfilter]]
=== Stop token filter
++++
<titleabbrev>Stop</titleabbrev>
++++

Removes {wikipedia}/Stop_words[stop words] from a token
stream.

When not customized, the filter removes the following English stop words by
default:

`a`, `an`, `and`, `are`, `as`, `at`, `be`, `but`, `by`, `for`, `if`, `in`,
`into`, `is`, `it`, `no`, `not`, `of`, `on`, `or`, `such`, `that`, `the`,
`their`, `then`, `there`, `these`, `they`, `this`, `to`, `was`, `will`, `with`

In addition to English, the `stop` filter supports predefined
<<analysis-stop-tokenfilter-stop-words-by-lang,stop word lists for several
languages>>. You can also specify your own stop words as an array or file.

The `stop` filter uses Lucene's
https://lucene.apache.org/core/{lucene_version_path}/core/org/apache/lucene/analysis/StopFilter.html[StopFilter].

[[analysis-stop-tokenfilter-analyze-ex]]
==== Example

The following analyze API request uses the `stop` filter to remove the stop words
`a` and `the` from `a quick fox jumps over the lazy dog`:

[source,console]
----
GET /_analyze
{
  "tokenizer": "standard",
  "filter": [ "stop" ],
  "text": "a quick fox jumps over the lazy dog"
}
----

The filter produces the following tokens:

[source,text]
----
[ quick, fox, jumps, over, lazy, dog ]
----

////
[source,console-result]
----
{
  "tokens": [
    {
      "token": "quick",
      "start_offset": 2,
      "end_offset": 7,
      "type": "<ALPHANUM>",
      "position": 1
    },
    {
      "token": "fox",
      "start_offset": 8,
      "end_offset": 11,
      "type": "<ALPHANUM>",
      "position": 2
    },
    {
      "token": "jumps",
      "start_offset": 12,
      "end_offset": 17,
      "type": "<ALPHANUM>",
      "position": 3
    },
    {
      "token": "over",
      "start_offset": 18,
      "end_offset": 22,
      "type": "<ALPHANUM>",
      "position": 4
    },
    {
      "token": "lazy",
      "start_offset": 27,
      "end_offset": 31,
      "type": "<ALPHANUM>",
      "position": 6
    },
    {
      "token": "dog",
      "start_offset": 32,
      "end_offset": 35,
      "type": "<ALPHANUM>",
      "position": 7
    }
  ]
}
----
////

[[analysis-stop-tokenfilter-analyzer-ex]]
==== Add to an analyzer

The following <<indices-create-index,create index API>> request uses the `stop`
filter to configure a new <<analysis-custom-analyzer,custom analyzer>>.

[source,console]
----
PUT /my-index-000001
{
  "settings": {
    "analysis": {
      "analyzer": {
        "my_analyzer": {
          "tokenizer": "whitespace",
          "filter": [ "stop" ]
        }
      }
    }
  }
}
----

[[analysis-stop-tokenfilter-configure-parms]]
==== Configurable parameters

`stopwords`::
+
--
(Optional, string or array of strings)
Language value, such as `_arabic_` or `_thai_`. Defaults to
<<english-stop-words,`_english_`>>.

Each language value corresponds to a predefined list of stop words in Lucene.
See <<analysis-stop-tokenfilter-stop-words-by-lang>> for supported language
values and their stop words.

Also accepts an array of stop words.

For an empty list of stop words, use `_none_`.
--

`stopwords_path`::
+
--
(Optional, string)
Path to a file that contains a list of stop words to remove.

This path must be absolute or relative to the `config` location, and the file
must be UTF-8 encoded. Each stop word in the file must be separated by a line
break.
--

`ignore_case`::
(Optional, Boolean)
If `true`, stop word matching is case insensitive. For example, if `true`, a
stop word of `the` matches and removes `The`, `THE`, or `the`. Defaults to
`false`.

`remove_trailing`::
+
--
(Optional, Boolean)
If `true`, the last token of a stream is removed if it's a stop word. Defaults
to `true`.

This parameter should be `false` when using the filter with a
<<completion-suggester,completion suggester>>. This would ensure a query like
`green a` matches and suggests `green apple` while still removing other stop
words.
--

[[analysis-stop-tokenfilter-customize]]
==== Customize

To customize the `stop` filter, duplicate it to create the basis
for a new custom token filter. You can modify the filter using its configurable
parameters.

For example, the following request creates a custom case-insensitive `stop`
filter that removes stop words from the <<english-stop-words,`_english_`>> stop
words list:

[source,console]
----
PUT /my-index-000001
{
  "settings": {
    "analysis": {
      "analyzer": {
        "default": {
          "tokenizer": "whitespace",
          "filter": [ "my_custom_stop_words_filter" ]
        }
      },
      "filter": {
        "my_custom_stop_words_filter": {
          "type": "stop",
          "ignore_case": true
        }
      }
    }
  }
}
----

You can also specify your own list of stop words. For example, the following
request creates a custom case-sensitive `stop` filter that removes only the stop
words `and`, `is`, and `the`:

[source,console]
----
PUT /my-index-000001
{
  "settings": {
    "analysis": {
      "analyzer": {
        "default": {
          "tokenizer": "whitespace",
          "filter": [ "my_custom_stop_words_filter" ]
        }
      },
      "filter": {
        "my_custom_stop_words_filter": {
          "type": "stop",
          "ignore_case": true,
          "stopwords": [ "and", "is", "the" ]
        }
      }
    }
  }
}
----

[[analysis-stop-tokenfilter-stop-words-by-lang]]
==== Stop words by language

The following list contains supported language values for the `stopwords`
parameter and a link to their predefined stop words in Lucene.

[[arabic-stop-words]]
`_arabic_`::
{lucene-stop-word-link}/ar/stopwords.txt[Arabic stop words]

[[armenian-stop-words]]
`_armenian_`::
{lucene-stop-word-link}/hy/stopwords.txt[Armenian stop words]

[[basque-stop-words]]
`_basque_`::
{lucene-stop-word-link}/eu/stopwords.txt[Basque stop words]

[[bengali-stop-words]]
`_bengali_`::
{lucene-stop-word-link}/bn/stopwords.txt[Bengali stop words]

[[brazilian-stop-words]]
`_brazilian_` (Brazilian Portuguese)::
{lucene-stop-word-link}/br/stopwords.txt[Brazilian Portuguese stop words]

[[bulgarian-stop-words]]
`_bulgarian_`::
{lucene-stop-word-link}/bg/stopwords.txt[Bulgarian stop words]

[[catalan-stop-words]]
`_catalan_`::
{lucene-stop-word-link}/ca/stopwords.txt[Catalan stop words]

[[cjk-stop-words]]
`_cjk_` (Chinese, Japanese, and Korean)::
{lucene-stop-word-link}/cjk/stopwords.txt[CJK stop words]

[[czech-stop-words]]
`_czech_`::
{lucene-stop-word-link}/cz/stopwords.txt[Czech stop words]

[[danish-stop-words]]
`_danish_`::
{lucene-stop-word-link}/snowball/danish_stop.txt[Danish stop words]

[[dutch-stop-words]]
`_dutch_`::
{lucene-stop-word-link}/snowball/dutch_stop.txt[Dutch stop words]

[[english-stop-words]]
`_english_`::
{lucene-gh-main-link}/analysis/common/src/java/org/apache/lucene/analysis/en/EnglishAnalyzer.java#L48[English stop words]

[[estonian-stop-words]]
`_estonian_`::
{lucene-stop-word-link}/et/stopwords.txt[Estonian stop words]

[[finnish-stop-words]]
`_finnish_`::
{lucene-stop-word-link}/snowball/finnish_stop.txt[Finnish stop words]

[[french-stop-words]]
`_french_`::
{lucene-stop-word-link}/snowball/french_stop.txt[French stop words]

[[galician-stop-words]]
`_galician_`::
{lucene-stop-word-link}/gl/stopwords.txt[Galician stop words]

[[german-stop-words]]
`_german_`::
{lucene-stop-word-link}/snowball/german_stop.txt[German stop words]

[[greek-stop-words]]
`_greek_`::
{lucene-stop-word-link}/el/stopwords.txt[Greek stop words]

[[hindi-stop-words]]
`_hindi_`::
{lucene-stop-word-link}/hi/stopwords.txt[Hindi stop words]

[[hungarian-stop-words]]
`_hungarian_`::
{lucene-stop-word-link}/snowball/hungarian_stop.txt[Hungarian stop words]

[[indonesian-stop-words]]
`_indonesian_`::
{lucene-stop-word-link}/id/stopwords.txt[Indonesian stop words]

[[irish-stop-words]]
`_irish_`::
{lucene-stop-word-link}/ga/stopwords.txt[Irish stop words]

[[italian-stop-words]]
`_italian_`::
{lucene-stop-word-link}/snowball/italian_stop.txt[Italian stop words]

[[latvian-stop-words]]
`_latvian_`::
{lucene-stop-word-link}/lv/stopwords.txt[Latvian stop words]

[[lithuanian-stop-words]]
`_lithuanian_`::
{lucene-stop-word-link}/lt/stopwords.txt[Lithuanian stop words]

[[norwegian-stop-words]]
`_norwegian_`::
{lucene-stop-word-link}/snowball/norwegian_stop.txt[Norwegian stop words]

[[persian-stop-words]]
`_persian_`::
{lucene-stop-word-link}/fa/stopwords.txt[Persian stop words]

[[portuguese-stop-words]]
`_portuguese_`::
{lucene-stop-word-link}/snowball/portuguese_stop.txt[Portuguese stop words]

[[romanian-stop-words]]
`_romanian_`::
{lucene-stop-word-link}/ro/stopwords.txt[Romanian stop words]

[[russian-stop-words]]
`_russian_`::
{lucene-stop-word-link}/snowball/russian_stop.txt[Russian stop words]

[[sorani-stop-words]]
`_sorani_`::
{lucene-stop-word-link}/ckb/stopwords.txt[Sorani stop words]

[[spanish-stop-words]]
`_spanish_`::
{lucene-stop-word-link}/snowball/spanish_stop.txt[Spanish stop words]

[[swedish-stop-words]]
`_swedish_`::
{lucene-stop-word-link}/snowball/swedish_stop.txt[Swedish stop words]

[[thai-stop-words]]
`_thai_`::
{lucene-stop-word-link}/th/stopwords.txt[Thai stop words]

[[turkish-stop-words]]
`_turkish_`::
{lucene-stop-word-link}/tr/stopwords.txt[Turkish stop words]