[Backport 2.18] [DOC] Tokenizers - Character group

_analyzers/tokenizers/character-group.md

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+---
+layout: default
+title: Character group
+parent: Tokenizers
+nav_order: 20
+has_children: false
+has_toc: false
+---
+
+# Character group tokenizer
+
+The `char_group` tokenizer splits text into tokens using specific characters as delimiters. It is suitable for situations requiring straightforward tokenization, offering a simpler alternative to pattern-based tokenizers without the added complexity.
+
+## Example usage
+
+The following example request creates a new index named `my_index` and configures an analyzer with a `char_group` tokenizer. The tokenizer splits text on white space, `-`, and `:` characters:
+
+```json
+PUT /my_index
+{
+  "settings": {
+    "analysis": {
+      "tokenizer": {
+        "my_char_group_tokenizer": {
+          "type": "char_group",
+          "tokenize_on_chars": [
+            "whitespace",
+            "-",
+            ":"
+          ]
+        }
+      },
+      "analyzer": {
+        "my_char_group_analyzer": {
+          "type": "custom",
+          "tokenizer": "my_char_group_tokenizer"
+        }
+      }
+    }
+  },
+  "mappings": {
+    "properties": {
+      "content": {
+        "type": "text",
+        "analyzer": "my_char_group_analyzer"
+      }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+## Generated tokens
+
+Use the following request to examine the tokens generated using the analyzer:
+
+```json
+POST /my_index/_analyze
+{
+  "analyzer": "my_char_group_analyzer",
+  "text": "Fast-driving cars: they drive fast!"
+}
+```
+{% include copy-curl.html %}
+
+The response contains the generated tokens:
+
+```json
+{
+  "tokens": [
+    {
+      "token": "Fast",
+      "start_offset": 0,
+      "end_offset": 4,
+      "type": "word",
+      "position": 0
+    },
+    {
+      "token": "driving",
+      "start_offset": 5,
+      "end_offset": 12,
+      "type": "word",
+      "position": 1
+    },
+    {
+      "token": "cars",
+      "start_offset": 13,
+      "end_offset": 17,
+      "type": "word",
+      "position": 2
+    },
+    {
+      "token": "they",
+      "start_offset": 19,
+      "end_offset": 23,
+      "type": "word",
+      "position": 3
+    },
+    {
+      "token": "drive",
+      "start_offset": 24,
+      "end_offset": 29,
+      "type": "word",
+      "position": 4
+    },
+    {
+      "token": "fast!",
+      "start_offset": 30,
+      "end_offset": 35,
+      "type": "word",
+      "position": 5
+    }
+  ]
+}
+```
+
+## Parameters
+
+The `char_group` tokenizer can be configured with the following parameters.
+
+| **Parameter**        | **Required/Optional** | **Data type** | **Description** |
+| :--- |  :--- |  :--- |  :--- |  
+| `tokenize_on_chars`   | Required              | Array         | Specifies a set of characters on which the text should be tokenized. You can specify single characters (for example, `-` or `@`), including escape characters (for example, `\n`), or character classes such as `whitespace`, `letter`, `digit`, `punctuation`, or `symbol`. |
+| `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`.  |