Standard tokenizer
The standard tokenizer is the default tokenizer in OpenSearch. It tokenizes text based on word boundaries using a grammar-based approach that recognizes letters, digits, and other characters like punctuation. It is highly versatile and suitable for many languages because it uses Unicode text segmentation rules (UAX#29) to break text into tokens.
Example usage
The following example request creates a new index named my_index and configures an analyzer with a standard tokenizer:
PUT /my_index
{
"settings": {
"analysis": {
"analyzer": {
"my_standard_analyzer": {
"type": "standard"
}
}
}
},
"mappings": {
"properties": {
"content": {
"type": "text",
"analyzer": "my_standard_analyzer"
}
}
}
}
Generated tokens
Use the following request to examine the tokens generated using the analyzer:
POST /my_index/_analyze
{
"analyzer": "my_standard_analyzer",
"text": "OpenSearch is powerful, fast, and scalable."
}
The response contains the generated tokens:
{
"tokens": [
{
"token": "opensearch",
"start_offset": 0,
"end_offset": 10,
"type": "<ALPHANUM>",
"position": 0
},
{
"token": "is",
"start_offset": 11,
"end_offset": 13,
"type": "<ALPHANUM>",
"position": 1
},
{
"token": "powerful",
"start_offset": 14,
"end_offset": 22,
"type": "<ALPHANUM>",
"position": 2
},
{
"token": "fast",
"start_offset": 24,
"end_offset": 28,
"type": "<ALPHANUM>",
"position": 3
},
{
"token": "and",
"start_offset": 30,
"end_offset": 33,
"type": "<ALPHANUM>",
"position": 4
},
{
"token": "scalable",
"start_offset": 34,
"end_offset": 42,
"type": "<ALPHANUM>",
"position": 5
}
]
}
Parameters
The standard tokenizer can be configured with the following parameter.
| 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. |