From 2d1d8172b6a6901671b99aa625fdc451faaa4160 Mon Sep 17 00:00:00 2001 From: AntonEliatra Date: Mon, 2 Dec 2024 13:55:03 +0000 Subject: [PATCH] Add length token filter docs #8152 (#8156) * Add length token filter docs #8152 Signed-off-by: Anton Rubin * Update length.md Signed-off-by: AntonEliatra * updating parameter table Signed-off-by: Anton Rubin * Doc review Signed-off-by: Fanit Kolchina * Apply suggestions from code review Co-authored-by: Nathan Bower Signed-off-by: kolchfa-aws <105444904+kolchfa-aws@users.noreply.github.com> --------- Signed-off-by: Anton Rubin Signed-off-by: AntonEliatra Signed-off-by: Fanit Kolchina Signed-off-by: kolchfa-aws <105444904+kolchfa-aws@users.noreply.github.com> Co-authored-by: Fanit Kolchina Co-authored-by: kolchfa-aws <105444904+kolchfa-aws@users.noreply.github.com> Co-authored-by: Nathan Bower --- _analyzers/token-filters/index.md | 2 +- _analyzers/token-filters/length.md | 91 ++++++++++++++++++++++++++++++ 2 files changed, 92 insertions(+), 1 deletion(-) create mode 100644 _analyzers/token-filters/length.md diff --git a/_analyzers/token-filters/index.md b/_analyzers/token-filters/index.md index 14abeab567..6ff348dd37 100644 --- a/_analyzers/token-filters/index.md +++ b/_analyzers/token-filters/index.md @@ -38,7 +38,7 @@ Token filter | Underlying Lucene token filter| Description `keyword_repeat` | [KeywordRepeatFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/KeywordRepeatFilter.html) | Emits each incoming token twice: once as a keyword and once as a non-keyword. `kstem` | [KStemFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/en/KStemFilter.html) | Provides kstem-based stemming for the English language. Combines algorithmic stemming with a built-in dictionary. `kuromoji_completion` | [JapaneseCompletionFilter](https://lucene.apache.org/core/9_10_0/analysis/kuromoji/org/apache/lucene/analysis/ja/JapaneseCompletionFilter.html) | Adds Japanese romanized terms to the token stream (in addition to the original tokens). Usually used to support autocomplete on Japanese search terms. Note that the filter has a `mode` parameter, which should be set to `index` when used in an index analyzer and `query` when used in a search analyzer. Requires the `analysis-kuromoji` plugin. For information about installing the plugin, see [Additional plugins]({{site.url}}{{site.baseurl}}/install-and-configure/plugins/#additional-plugins). -`length` | [LengthFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LengthFilter.html) | Removes tokens whose lengths are shorter or longer than the length range specified by `min` and `max`. +[`length`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/length/) | [LengthFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LengthFilter.html) | Removes tokens that are shorter or longer than the length range specified by `min` and `max`. `limit` | [LimitTokenCountFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LimitTokenCountFilter.html) | Limits the number of output tokens. A common use case is to limit the size of document field values based on token count. `lowercase` | [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) | Converts tokens to lowercase. The default [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) is for the English language. You can set the `language` parameter to `greek` (uses [GreekLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/el/GreekLowerCaseFilter.html)), `irish` (uses [IrishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ga/IrishLowerCaseFilter.html)), or `turkish` (uses [TurkishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/tr/TurkishLowerCaseFilter.html)). [`min_hash`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/min-hash/) | [MinHashFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/minhash/MinHashFilter.html) | Uses the [MinHash technique](https://en.wikipedia.org/wiki/MinHash) to estimate document similarity. Performs the following operations on a token stream sequentially:
1. Hashes each token in the stream.
2. Assigns the hashes to buckets, keeping only the smallest hashes of each bucket.
3. Outputs the smallest hash from each bucket as a token stream. diff --git a/_analyzers/token-filters/length.md b/_analyzers/token-filters/length.md new file mode 100644 index 0000000000..f6c5dcc706 --- /dev/null +++ b/_analyzers/token-filters/length.md @@ -0,0 +1,91 @@ +--- +layout: default +title: Length +parent: Token filters +nav_order: 240 +--- + +# Length token filter + +The `length` token filter is used to remove tokens that don't meet specified length criteria (minimum and maximum values) from the token stream. + +## Parameters + +The `length` token filter can be configured with the following parameters. + +Parameter | Required/Optional | Data type | Description +:--- | :--- | :--- | :--- +`min` | Optional | Integer | The minimum token length. Default is `0`. +`max` | Optional | Integer | The maximum token length. Default is `Integer.MAX_VALUE` (`2147483647`). + + +## Example + +The following example request creates a new index named `my_index` and configures an analyzer with a `length` filter: + +```json +PUT my_index +{ + "settings": { + "analysis": { + "analyzer": { + "only_keep_4_to_10_characters": { + "tokenizer": "whitespace", + "filter": [ "length_4_to_10" ] + } + }, + "filter": { + "length_4_to_10": { + "type": "length", + "min": 4, + "max": 10 + } + } + } + } +} +``` +{% include copy-curl.html %} + +## Generated tokens + +Use the following request to examine the tokens generated using the analyzer: + +```json +GET /my_index/_analyze +{ + "analyzer": "only_keep_4_to_10_characters", + "text": "OpenSearch is a great tool!" +} +``` +{% include copy-curl.html %} + +The response contains the generated tokens: + +```json +{ + "tokens": [ + { + "token": "OpenSearch", + "start_offset": 0, + "end_offset": 10, + "type": "word", + "position": 0 + }, + { + "token": "great", + "start_offset": 16, + "end_offset": 21, + "type": "word", + "position": 3 + }, + { + "token": "tool!", + "start_offset": 22, + "end_offset": 27, + "type": "word", + "position": 4 + } + ] +} +```