Add lowercase token filter docs #8162
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,82 @@ | ||
| --- | ||
| layout: default | ||
| title: Lowercase | ||
| parent: Token filters | ||
| nav_order: 260 | ||
| --- | ||
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| # Lowercase token filter | ||
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| The `lowercase` token filter is used to convert all characters in the token stream to lowercase, making searches case insensitive. | ||
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| ## Parameters | ||
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| The `lowercase` token filter can be configured with the following parameter. | ||
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| Parameter | Required/Optional | Description | ||
| :--- | :--- | :--- | ||
| `language` | Optional | Specifies a language-specific token filter. Valid values are: <br>- [`greek`](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/el/GreekLowerCaseFilter.html) <br>- [`irish`](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/ga/IrishLowerCaseFilter.html) <br>- [`turkish`](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/tr/TurkishLowerCaseFilter.html). <br> Default is the [Lucene LowerCaseFilter](https://lucene.apache.org/core/8_7_0/analyzers-common/org/apache/lucene/analysis/core/LowerCaseFilter.html). | ||
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There was a problem hiding this comment. Line 18: Is There was a problem hiding this comment. Default without specifying a language. |
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| ## Example | ||
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| The following example request creates a new index named `custom_lowercase_example`. It configures an analyzer with a `lowercase` filter and specifies `greek` as the `language`: | ||
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| ```json | ||
| PUT /custom_lowercase_example | ||
| { | ||
| "settings": { | ||
| "analysis": { | ||
| "analyzer": { | ||
| "greek_lowercase_example": { | ||
| "type": "custom", | ||
| "tokenizer": "standard", | ||
| "filter": ["greek_lowercase"] | ||
| } | ||
| }, | ||
| "filter": { | ||
| "greek_lowercase": { | ||
| "type": "lowercase", | ||
| "language": "greek" | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
| ``` | ||
| {% include copy-curl.html %} | ||
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| ## Generated tokens | ||
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| Use the following request to examine the tokens generated using the analyzer: | ||
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| ```json | ||
| GET /custom_lowercase_example/_analyze | ||
| { | ||
| "analyzer": "greek_lowercase_example", | ||
| "text": "Αθήνα ΕΛΛΑΔΑ" | ||
| } | ||
| ``` | ||
| {% include copy-curl.html %} | ||
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| The response contains the generated tokens: | ||
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| ```json | ||
| { | ||
| "tokens": [ | ||
| { | ||
| "token": "αθηνα", | ||
| "start_offset": 0, | ||
| "end_offset": 5, | ||
| "type": "<ALPHANUM>", | ||
| "position": 0 | ||
| }, | ||
| { | ||
| "token": "ελλαδα", | ||
| "start_offset": 6, | ||
| "end_offset": 12, | ||
| "type": "<ALPHANUM>", | ||
| "position": 1 | ||
| } | ||
| ] | ||
| } | ||
| ``` | ||
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Line 41: Confirm the accuracy of my changes.
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Not quite: the default specifies no language and processes English. There are also a couple of other language options. Reworded.