add stop analyzer docs (#8534)

* add stop analyzer docs Signed-off-by: Anton Rubin <[email protected]> * adding more details Signed-off-by: Anton Rubin <[email protected]> * updating parameter table Signed-off-by: Anton Rubin <[email protected]> * Doc review Signed-off-by: Fanit Kolchina <[email protected]> * Update _analyzers/stop.md Co-authored-by: Nathan Bower <[email protected]> Signed-off-by: kolchfa-aws <[email protected]> * Update _analyzers/stop.md Signed-off-by: kolchfa-aws <[email protected]> * Add file path example Signed-off-by: Fanit Kolchina <[email protected]> --------- Signed-off-by: Anton Rubin <[email protected]> Signed-off-by: Fanit Kolchina <[email protected]> Signed-off-by: kolchfa-aws <[email protected]> Co-authored-by: Fanit Kolchina <[email protected]> Co-authored-by: kolchfa-aws <[email protected]> Co-authored-by: Nathan Bower <[email protected]> (cherry picked from commit 7d1151c) Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
opensearch-project · Dec 10, 2024 · 12e750d · 12e750d
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+---
+layout: default
+title: Stop analyzer
+nav_order: 70
+---
+
+# Stop analyzer
+
+The `stop` analyzer removes a predefined list of stopwords. This analyzer consists of a `lowercase` tokenizer and a `stop` token filter.
+
+## Parameters
+
+You can configure a `stop` analyzer with the following parameters.
+
+Parameter | Required/Optional | Data type | Description
+:--- | :--- | :--- | :--- 
+`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 `_english_`.
+`stopwords_path` | Optional | String | The path (absolute or relative to the config directory) to the file containing a list of stopwords.
+
+## Example
+
+Use the following command to create an index named `my_stop_index` with a `stop` analyzer:
+
+```json
+PUT /my_stop_index
+{
+  "mappings": {
+    "properties": {
+      "my_field": {
+        "type": "text",
+        "analyzer": "stop"
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+## Configuring a custom analyzer
+
+Use the following command to configure an index with a custom analyzer that is equivalent to a `stop` analyzer:
+
+```json
+PUT /my_custom_stop_analyzer_index
+{
+  "settings": {
+    "analysis": {
+      "analyzer": {
+        "my_custom_stop_analyzer": {
+          "tokenizer": "lowercase",
+          "filter": [
+            "stop"
+          ]
+        }
+      }
+    }
+  },
+  "mappings": {
+    "properties": {
+      "my_field": {
+        "type": "text",
+        "analyzer": "my_custom_stop_analyzer"
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+## Generated tokens
+
+Use the following request to examine the tokens generated using the analyzer:
+
+```json
+POST /my_custom_stop_analyzer_index/_analyze
+{
+  "analyzer": "my_custom_stop_analyzer",
+  "text": "The large turtle is green and brown"
+}
+```
+{% include copy-curl.html %}
+
+The response contains the generated tokens:
+
+```json
+{
+  "tokens": [
+    {
+      "token": "large",
+      "start_offset": 4,
+      "end_offset": 9,
+      "type": "word",
+      "position": 1
+    },
+    {
+      "token": "turtle",
+      "start_offset": 10,
+      "end_offset": 16,
+      "type": "word",
+      "position": 2
+    },
+    {
+      "token": "green",
+      "start_offset": 20,
+      "end_offset": 25,
+      "type": "word",
+      "position": 4
+    },
+    {
+      "token": "brown",
+      "start_offset": 30,
+      "end_offset": 35,
+      "type": "word",
+      "position": 6
+    }
+  ]
+}
+```
+
+# Specifying stopwords
+
+The following example request specifies a custom list of stopwords:
+
+```json
+PUT /my_new_custom_stop_index
+{
+  "settings": {
+    "analysis": {
+      "analyzer": {
+        "my_custom_stop_analyzer": {
+          "type": "stop",                     
+          "stopwords": ["is", "and", "was"]
+        }
+      }
+    }
+  },
+  "mappings": {
+    "properties": {
+      "description": {
+        "type": "text",
+        "analyzer": "my_custom_stop_analyzer" 
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+The following example request specifies a path to the file containing stopwords:
+
+```json
+PUT /my_new_custom_stop_index
+{
+  "settings": {
+    "analysis": {
+      "analyzer": {
+        "my_custom_stop_analyzer": {
+          "type": "stop",                     
+          "stopwords_path": "stopwords.txt"
+        }
+      }
+    }
+  },
+  "mappings": {
+    "properties": {
+      "description": {
+        "type": "text",
+        "analyzer": "my_custom_stop_analyzer" 
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+In this example, the file is located in the config directory. You can also specify a full path to the file.