277 lines
5.5 KiB
Plaintext
277 lines
5.5 KiB
Plaintext
[[analysis-stop-analyzer]]
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=== Stop analyzer
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++++
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<titleabbrev>Stop</titleabbrev>
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++++
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The `stop` analyzer is the same as the <<analysis-simple-analyzer,`simple` analyzer>>
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but adds support for removing stop words. It defaults to using the
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`_english_` stop words.
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[discrete]
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=== Example output
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[source,console]
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---------------------------
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POST _analyze
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{
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"analyzer": "stop",
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"text": "The 2 QUICK Brown-Foxes jumped over the lazy dog's bone."
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}
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---------------------------
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/////////////////////
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[source,console-result]
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----------------------------
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{
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"tokens": [
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{
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"token": "quick",
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"start_offset": 6,
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"end_offset": 11,
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"type": "word",
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"position": 1
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},
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{
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"token": "brown",
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"start_offset": 12,
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"end_offset": 17,
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"type": "word",
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"position": 2
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},
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{
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"token": "foxes",
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"start_offset": 18,
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"end_offset": 23,
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"type": "word",
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"position": 3
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},
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{
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"token": "jumped",
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"start_offset": 24,
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"end_offset": 30,
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"type": "word",
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"position": 4
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},
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{
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"token": "over",
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"start_offset": 31,
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"end_offset": 35,
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"type": "word",
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"position": 5
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},
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{
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"token": "lazy",
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"start_offset": 40,
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"end_offset": 44,
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"type": "word",
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"position": 7
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},
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{
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"token": "dog",
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"start_offset": 45,
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"end_offset": 48,
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"type": "word",
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"position": 8
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},
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{
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"token": "s",
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"start_offset": 49,
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"end_offset": 50,
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"type": "word",
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"position": 9
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},
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{
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"token": "bone",
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"start_offset": 51,
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"end_offset": 55,
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"type": "word",
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"position": 10
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}
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]
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}
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----------------------------
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/////////////////////
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The above sentence would produce the following terms:
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[source,text]
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---------------------------
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[ quick, brown, foxes, jumped, over, lazy, dog, s, bone ]
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---------------------------
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[discrete]
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=== Configuration
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The `stop` analyzer accepts the following parameters:
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[horizontal]
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`stopwords`::
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A pre-defined stop words list like `_english_` or an array containing a
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list of stop words. Defaults to `_english_`.
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`stopwords_path`::
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The path to a file containing stop words. This path is relative to the
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Elasticsearch `config` directory.
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See the <<analysis-stop-tokenfilter,Stop Token Filter>> for more information
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about stop word configuration.
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[discrete]
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=== Example configuration
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In this example, we configure the `stop` analyzer to use a specified list of
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words as stop words:
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[source,console]
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----------------------------
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PUT my-index-000001
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{
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"settings": {
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"analysis": {
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"analyzer": {
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"my_stop_analyzer": {
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"type": "stop",
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"stopwords": ["the", "over"]
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}
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}
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}
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}
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}
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POST my-index-000001/_analyze
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{
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"analyzer": "my_stop_analyzer",
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"text": "The 2 QUICK Brown-Foxes jumped over the lazy dog's bone."
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}
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----------------------------
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/////////////////////
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[source,console-result]
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----------------------------
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{
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"tokens": [
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{
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"token": "quick",
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"start_offset": 6,
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"end_offset": 11,
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"type": "word",
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"position": 1
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},
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{
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"token": "brown",
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"start_offset": 12,
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"end_offset": 17,
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"type": "word",
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"position": 2
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},
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{
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"token": "foxes",
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"start_offset": 18,
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"end_offset": 23,
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"type": "word",
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"position": 3
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},
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{
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"token": "jumped",
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"start_offset": 24,
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"end_offset": 30,
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"type": "word",
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"position": 4
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},
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{
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"token": "lazy",
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"start_offset": 40,
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"end_offset": 44,
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"type": "word",
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"position": 7
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},
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{
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"token": "dog",
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"start_offset": 45,
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"end_offset": 48,
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"type": "word",
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"position": 8
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},
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{
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"token": "s",
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"start_offset": 49,
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"end_offset": 50,
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"type": "word",
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"position": 9
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},
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{
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"token": "bone",
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"start_offset": 51,
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"end_offset": 55,
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"type": "word",
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"position": 10
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}
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]
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}
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----------------------------
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/////////////////////
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The above example produces the following terms:
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[source,text]
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---------------------------
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[ quick, brown, foxes, jumped, lazy, dog, s, bone ]
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---------------------------
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[discrete]
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=== Definition
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It consists of:
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Tokenizer::
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* <<analysis-lowercase-tokenizer,Lower Case Tokenizer>>
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Token filters::
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* <<analysis-stop-tokenfilter,Stop Token Filter>>
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If you need to customize the `stop` analyzer beyond the configuration
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parameters then you need to recreate it as a `custom` analyzer and modify
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it, usually by adding token filters. This would recreate the built-in
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`stop` analyzer and you can use it as a starting point for further
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customization:
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[source,console]
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----------------------------------------------------
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PUT /stop_example
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{
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"settings": {
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"analysis": {
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"filter": {
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"english_stop": {
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"type": "stop",
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"stopwords": "_english_" <1>
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}
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},
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"analyzer": {
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"rebuilt_stop": {
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"tokenizer": "lowercase",
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"filter": [
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"english_stop" <2>
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]
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}
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}
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}
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}
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}
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----------------------------------------------------
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// TEST[s/\n$/\nstartyaml\n - compare_analyzers: {index: stop_example, first: stop, second: rebuilt_stop}\nendyaml\n/]
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<1> The default stopwords can be overridden with the `stopwords`
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or `stopwords_path` parameters.
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<2> You'd add any token filters after `english_stop`.
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