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88 changes: 53 additions & 35 deletions _analyzers/supported-analyzers/standard.md
Original file line number Diff line number Diff line change
Expand Up @@ -7,17 +7,20 @@

# Standard analyzer

The `standard` analyzer is the default analyzer used when no other analyzer is specified. It is designed to provide a basic and efficient approach to generic text processing.
The `standard` analyzer is the built-in default analyzer used for general-purpose full-text search in OpenSearch. It is designed to provide consistent, language-agnostic text processing by efficiently breaking down text into searchable terms.

This analyzer consists of the following tokenizers and token filters:
The `standard` analyzer performs the following operations:

- `standard` tokenizer: Removes most punctuation and splits text on spaces and other common delimiters.
- `lowercase` token filter: Converts all tokens to lowercase, ensuring case-insensitive matching.
- `stop` token filter: Removes common stopwords, such as "the", "is", and "and", from the tokenized output.
- **Tokenization**: It uses the [`standard`]({{site.url}}{{site.baseurl}}/analyzers/tokenizers/standard/) tokenizer, which splits text into words based on Unicode text segmentation rules, handling spaces, punctuation, and common delimiters.
- **Lowercasing**: It applies the [`lowercase`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/lowercase/) token filter to convert all tokens to lowercase, ensuring consistent matching regardless of input case.

Check failure on line 15 in _analyzers/supported-analyzers/standard.md

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[vale] reported by reviewdog 🐶 [OpenSearch.Spelling] Error: Lowercasing. If you are referencing a setting, variable, format, function, or repository, surround it with tic marks. Raw Output: {"message": "[OpenSearch.Spelling] Error: Lowercasing. If you are referencing a setting, variable, format, function, or repository, surround it with tic marks.", "location": {"path": "_analyzers/supported-analyzers/standard.md", "range": {"start": {"line": 15, "column": 5}}}, "severity": "ERROR"}

## Example
This combination makes the `standard` analyzer ideal for indexing a wide range of natural language content without needing language-specific customizations.

Use the following command to create an index named `my_standard_index` with a `standard` analyzer:
---

## Example: Creating an index with the standard analyzer

You can assign the `standard` analyzer to a text field when creating an index:

```json
PUT /my_standard_index
Expand All @@ -26,41 +29,41 @@
"properties": {
"my_field": {
"type": "text",
"analyzer": "standard"
"analyzer": "standard"
}
}
}
}
```
{% include copy-curl.html %}

## Parameters
---

You can configure a `standard` analyzer with the following parameters.
## Parameters

Parameter | Required/Optional | Data type | Description
:--- | :--- | :--- | :---
`max_token_length` | Optional | Integer | Sets the maximum length of the produced token. If this length is exceeded, the token is split into multiple tokens at the length configured in `max_token_length`. Default is `255`.
`stopwords` | Optional | String or list of strings | A string specifying a predefined list of stopwords (such as `_english_`) or an array specifying a custom list of stopwords. Default is `_none_`.
`stopwords_path` | Optional | String | The path (absolute or relative to the config directory) to the file containing a list of stop words.
The `standard` analyzer supports the following parameters:

| Parameter | Type | Default | Description |
|:----------|:-----|:--------|:------------|
| `max_token_length` | Integer | `255` | Sets the maximum length of a token before it is split. |
| `stopwords` | List or String | None | A list of stopwords or a predefined stopword set like `_english_` to remove during analysis. |
| `stopwords_path` | String | None | Path to a file containing stopwords to be used during analysis. |

## Configuring a custom analyzer
## Example: Analyzer with parameters

Use the following command to configure an index with a custom analyzer that is equivalent to the `standard` analyzer:
The following example crated index `products` and configures `max_token_length` and `stopwords`:

```json
PUT /my_custom_index
PUT /animals
{
"settings": {
"analysis": {
"analyzer": {
"my_custom_analyzer": {
"type": "custom",
"tokenizer": "standard",
"filter": [
"lowercase",
"stop"
"my_manual_stopwords_analyzer": {
"type": "standard",
"max_token_length": 10,
"stopwords": [
"the", "is", "and", "but", "an", "a", "it"
]
}
}
Expand All @@ -70,28 +73,43 @@
```
{% include copy-curl.html %}

## Generated tokens

Use the following request to examine the tokens generated using the analyzer:
Use the following `_analyze` API to see how the `my_manual_stopwords_analyzer` processes text:

```json
POST /my_custom_index/_analyze
POST /animals/_analyze
{
"analyzer": "my_custom_analyzer",
"text": "The slow turtle swims away"
"analyzer": "my_manual_stopwords_analyzer",
"text": "The Turtle is Large but it is Slow"
}
```
{% include copy-curl.html %}

The response contains the generated tokens:
The returned token are separated based on spacing, lowercased and stopwords are removed:

```json
{
"tokens": [
{"token": "slow","start_offset": 4,"end_offset": 8,"type": "<ALPHANUM>","position": 1},
{"token": "turtle","start_offset": 9,"end_offset": 15,"type": "<ALPHANUM>","position": 2},
{"token": "swims","start_offset": 16,"end_offset": 21,"type": "<ALPHANUM>","position": 3},
{"token": "away","start_offset": 22,"end_offset": 26,"type": "<ALPHANUM>","position": 4}
{
"token": "turtle",
"start_offset": 4,
"end_offset": 10,
"type": "<ALPHANUM>",
"position": 1
},
{
"token": "large",
"start_offset": 14,
"end_offset": 19,
"type": "<ALPHANUM>",
"position": 3
},
{
"token": "slow",
"start_offset": 30,
"end_offset": 34,
"type": "<ALPHANUM>",
"position": 7
}
]
}
```
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