# groonga - An open-source fulltext search engine and column store.

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# 7.3.44. `tokenize`

## 7.3.44.1. Summary

`tokenize` command tokenizes text by the specified tokenizer. It is useful to debug tokenization.

## 7.3.44.2. Syntax

`tokenize` command has required parameters and optional parameters. `tokenizer` and `string` are required parameters. Others are optional:

    tokenize tokenizer
             string
             [normalizer=null]
             [flags=NONE]
             [mode=ADD]
             [token_filters=NONE]

## 7.3.44.3. Usage

Here is a simple example.

Execution example:

    tokenize TokenBigram "Fulltext Search"
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "Fu"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "ul"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "ll"
    #     },
    #     {
    #       "position": 3,
    #       "force_prefix": false,
    #       "value": "lt"
    #     },
    #     {
    #       "position": 4,
    #       "force_prefix": false,
    #       "value": "te"
    #     },
    #     {
    #       "position": 5,
    #       "force_prefix": false,
    #       "value": "ex"
    #     },
    #     {
    #       "position": 6,
    #       "force_prefix": false,
    #       "value": "xt"
    #     },
    #     {
    #       "position": 7,
    #       "force_prefix": false,
    #       "value": "t "
    #     },
    #     {
    #       "position": 8,
    #       "force_prefix": false,
    #       "value": " S"
    #     },
    #     {
    #       "position": 9,
    #       "force_prefix": false,
    #       "value": "Se"
    #     },
    #     {
    #       "position": 10,
    #       "force_prefix": false,
    #       "value": "ea"
    #     },
    #     {
    #       "position": 11,
    #       "force_prefix": false,
    #       "value": "ar"
    #     },
    #     {
    #       "position": 12,
    #       "force_prefix": false,
    #       "value": "rc"
    #     },
    #     {
    #       "position": 13,
    #       "force_prefix": false,
    #       "value": "ch"
    #     },
    #     {
    #       "position": 14,
    #       "force_prefix": false,
    #       "value": "h"
    #     }
    #   ]
    # ]

It has only required parameters. `tokenizer` is `TokenBigram` and `string` is `"Fulltext Search"`. It returns tokens that is generated by tokenizing `"Fulltext Search"` with `TokenBigram` tokenizer. It doesn't normalize `"Fulltext Search"`.

## 7.3.44.4. Parameters

This section describes all parameters. Parameters are categorized.

### 7.3.44.4.1. Required parameters

There are required parameters, `tokenizer` and `string`.

#### 7.3.44.4.1.1. `tokenizer`

Specifies the tokenizer name. `tokenize` command uses the tokenizer that is named `tokenizer`.

See Tokenizers about built-in tokenizers.

Here is an example to use built-in `TokenTrigram` tokenizer.

Execution example:

    tokenize TokenTrigram "Fulltext Search"
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "Ful"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "ull"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "llt"
    #     },
    #     {
    #       "position": 3,
    #       "force_prefix": false,
    #       "value": "lte"
    #     },
    #     {
    #       "position": 4,
    #       "force_prefix": false,
    #       "value": "tex"
    #     },
    #     {
    #       "position": 5,
    #       "force_prefix": false,
    #       "value": "ext"
    #     },
    #     {
    #       "position": 6,
    #       "force_prefix": false,
    #       "value": "xt "
    #     },
    #     {
    #       "position": 7,
    #       "force_prefix": false,
    #       "value": "t S"
    #     },
    #     {
    #       "position": 8,
    #       "force_prefix": false,
    #       "value": " Se"
    #     },
    #     {
    #       "position": 9,
    #       "force_prefix": false,
    #       "value": "Sea"
    #     },
    #     {
    #       "position": 10,
    #       "force_prefix": false,
    #       "value": "ear"
    #     },
    #     {
    #       "position": 11,
    #       "force_prefix": false,
    #       "value": "arc"
    #     },
    #     {
    #       "position": 12,
    #       "force_prefix": false,
    #       "value": "rch"
    #     },
    #     {
    #       "position": 13,
    #       "force_prefix": false,
    #       "value": "ch"
    #     },
    #     {
    #       "position": 14,
    #       "force_prefix": false,
    #       "value": "h"
    #     }
    #   ]
    # ]

If you want to use other tokenizers, you need to register additional tokenizer plugin by register command. For example, you can use KyTea based tokenizer by registering `tokenizers/kytea`.

#### 7.3.44.4.1.2. `string`

Specifies any string which you want to tokenize.

If you want to include spaces in `string`, you need to quote `string` by single quotation (`'`) or double quotation (`"`).

Here is an example to use spaces in `string`.

Execution example:

    tokenize TokenBigram "Groonga is a fast fulltext earch engine!"
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "Gr"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "ro"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "oo"
    #     },
    #     {
    #       "position": 3,
    #       "force_prefix": false,
    #       "value": "on"
    #     },
    #     {
    #       "position": 4,
    #       "force_prefix": false,
    #       "value": "ng"
    #     },
    #     {
    #       "position": 5,
    #       "force_prefix": false,
    #       "value": "ga"
    #     },
    #     {
    #       "position": 6,
    #       "force_prefix": false,
    #       "value": "a "
    #     },
    #     {
    #       "position": 7,
    #       "force_prefix": false,
    #       "value": " i"
    #     },
    #     {
    #       "position": 8,
    #       "force_prefix": false,
    #       "value": "is"
    #     },
    #     {
    #       "position": 9,
    #       "force_prefix": false,
    #       "value": "s "
    #     },
    #     {
    #       "position": 10,
    #       "force_prefix": false,
    #       "value": " a"
    #     },
    #     {
    #       "position": 11,
    #       "force_prefix": false,
    #       "value": "a "
    #     },
    #     {
    #       "position": 12,
    #       "force_prefix": false,
    #       "value": " f"
    #     },
    #     {
    #       "position": 13,
    #       "force_prefix": false,
    #       "value": "fa"
    #     },
    #     {
    #       "position": 14,
    #       "force_prefix": false,
    #       "value": "as"
    #     },
    #     {
    #       "position": 15,
    #       "force_prefix": false,
    #       "value": "st"
    #     },
    #     {
    #       "position": 16,
    #       "force_prefix": false,
    #       "value": "t "
    #     },
    #     {
    #       "position": 17,
    #       "force_prefix": false,
    #       "value": " f"
    #     },
    #     {
    #       "position": 18,
    #       "force_prefix": false,
    #       "value": "fu"
    #     },
    #     {
    #       "position": 19,
    #       "force_prefix": false,
    #       "value": "ul"
    #     },
    #     {
    #       "position": 20,
    #       "force_prefix": false,
    #       "value": "ll"
    #     },
    #     {
    #       "position": 21,
    #       "force_prefix": false,
    #       "value": "lt"
    #     },
    #     {
    #       "position": 22,
    #       "force_prefix": false,
    #       "value": "te"
    #     },
    #     {
    #       "position": 23,
    #       "force_prefix": false,
    #       "value": "ex"
    #     },
    #     {
    #       "position": 24,
    #       "force_prefix": false,
    #       "value": "xt"
    #     },
    #     {
    #       "position": 25,
    #       "force_prefix": false,
    #       "value": "t "
    #     },
    #     {
    #       "position": 26,
    #       "force_prefix": false,
    #       "value": " e"
    #     },
    #     {
    #       "position": 27,
    #       "force_prefix": false,
    #       "value": "ea"
    #     },
    #     {
    #       "position": 28,
    #       "force_prefix": false,
    #       "value": "ar"
    #     },
    #     {
    #       "position": 29,
    #       "force_prefix": false,
    #       "value": "rc"
    #     },
    #     {
    #       "position": 30,
    #       "force_prefix": false,
    #       "value": "ch"
    #     },
    #     {
    #       "position": 31,
    #       "force_prefix": false,
    #       "value": "h "
    #     },
    #     {
    #       "position": 32,
    #       "force_prefix": false,
    #       "value": " e"
    #     },
    #     {
    #       "position": 33,
    #       "force_prefix": false,
    #       "value": "en"
    #     },
    #     {
    #       "position": 34,
    #       "force_prefix": false,
    #       "value": "ng"
    #     },
    #     {
    #       "position": 35,
    #       "force_prefix": false,
    #       "value": "gi"
    #     },
    #     {
    #       "position": 36,
    #       "force_prefix": false,
    #       "value": "in"
    #     },
    #     {
    #       "position": 37,
    #       "force_prefix": false,
    #       "value": "ne"
    #     },
    #     {
    #       "position": 38,
    #       "force_prefix": false,
    #       "value": "e!"
    #     },
    #     {
    #       "position": 39,
    #       "force_prefix": false,
    #       "value": "!"
    #     }
    #   ]
    # ]

### 7.3.44.4.2. Optional parameters

There are optional parameters.

#### 7.3.44.4.2.1. `normalizer`

Specifies the normalizer name. `tokenize` command uses the normalizer that is named `normalizer`. Normalizer is important for N-gram family tokenizers such as `TokenBigram`.

Normalizer detects character type for each character while normalizing. N-gram family tokenizers use character types while tokenizing.

Here is an example that doesn't use normalizer.

Execution example:

    tokenize TokenBigram "Fulltext Search"
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "Fu"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "ul"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "ll"
    #     },
    #     {
    #       "position": 3,
    #       "force_prefix": false,
    #       "value": "lt"
    #     },
    #     {
    #       "position": 4,
    #       "force_prefix": false,
    #       "value": "te"
    #     },
    #     {
    #       "position": 5,
    #       "force_prefix": false,
    #       "value": "ex"
    #     },
    #     {
    #       "position": 6,
    #       "force_prefix": false,
    #       "value": "xt"
    #     },
    #     {
    #       "position": 7,
    #       "force_prefix": false,
    #       "value": "t "
    #     },
    #     {
    #       "position": 8,
    #       "force_prefix": false,
    #       "value": " S"
    #     },
    #     {
    #       "position": 9,
    #       "force_prefix": false,
    #       "value": "Se"
    #     },
    #     {
    #       "position": 10,
    #       "force_prefix": false,
    #       "value": "ea"
    #     },
    #     {
    #       "position": 11,
    #       "force_prefix": false,
    #       "value": "ar"
    #     },
    #     {
    #       "position": 12,
    #       "force_prefix": false,
    #       "value": "rc"
    #     },
    #     {
    #       "position": 13,
    #       "force_prefix": false,
    #       "value": "ch"
    #     },
    #     {
    #       "position": 14,
    #       "force_prefix": false,
    #       "value": "h"
    #     }
    #   ]
    # ]

All alphabets are tokenized by two characters. For example, `Fu` is a token.

Here is an example that uses normalizer.

Execution example:

    tokenize TokenBigram "Fulltext Search" NormalizerAuto
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "fulltext"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "search"
    #     }
    #   ]
    # ]

Continuous alphabets are tokenized as one token. For example, `fulltext` is a token.

If you want to tokenize by two characters with noramlizer, use `TokenBigramSplitSymbolAlpha`.

Execution example:

    tokenize TokenBigramSplitSymbolAlpha "Fulltext Search" NormalizerAuto
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "fu"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "ul"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "ll"
    #     },
    #     {
    #       "position": 3,
    #       "force_prefix": false,
    #       "value": "lt"
    #     },
    #     {
    #       "position": 4,
    #       "force_prefix": false,
    #       "value": "te"
    #     },
    #     {
    #       "position": 5,
    #       "force_prefix": false,
    #       "value": "ex"
    #     },
    #     {
    #       "position": 6,
    #       "force_prefix": false,
    #       "value": "xt"
    #     },
    #     {
    #       "position": 7,
    #       "force_prefix": false,
    #       "value": "t"
    #     },
    #     {
    #       "position": 8,
    #       "force_prefix": false,
    #       "value": "se"
    #     },
    #     {
    #       "position": 9,
    #       "force_prefix": false,
    #       "value": "ea"
    #     },
    #     {
    #       "position": 10,
    #       "force_prefix": false,
    #       "value": "ar"
    #     },
    #     {
    #       "position": 11,
    #       "force_prefix": false,
    #       "value": "rc"
    #     },
    #     {
    #       "position": 12,
    #       "force_prefix": false,
    #       "value": "ch"
    #     },
    #     {
    #       "position": 13,
    #       "force_prefix": false,
    #       "value": "h"
    #     }
    #   ]
    # ]

All alphabets are tokenized by two characters. And they are normalized to lower case characters. For example, `fu` is a token.

#### 7.3.44.4.2.2. `flags`

Specifies a tokenization customize options. You can specify multiple options separated by "`|`". For example, `NONE|ENABLE_TOKENIZED_DELIMITER`.

Here are available flags.

Flag | Description
--- | ---
`NONE` | Just ignored.
`ENABLE_TOKENIZED_DELIMITER` | Enables tokenized delimiter. See Tokenizers about tokenized delimiter details.

Here is an example that uses `ENABLE_TOKENIZED_DELIMITER`.

Execution example:

    tokenize TokenDelimit "Fulltext Seacrch" NormalizerAuto ENABLE_TOKENIZED_DELIMITER
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "full"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "text sea"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "crch"
    #     }
    #   ]
    # ]

`TokenDelimit` tokenizer is one of tokenized delimiter supported tokenizer. `ENABLE_TOKENIZED_DELIMITER` enables tokenized delimiter. Tokenized delimiter is special character that indicates token border. It is `U+FFFE`. The character is not assigned any character. It means that the character is not appeared in normal string. So the character is good character for this puropose. If `ENABLE_TOKENIZED_DELIMITER` is enabled, the target string is treated as already tokenized string. Tokenizer just tokenizes by tokenized delimiter.

#### 7.3.44.4.2.3. `mode`

Specifies a tokenize mode. If the mode is specified `ADD`, the text is tokenized by the rule that adding a document. If the mode is specified `GET`, the text is tokenized by the rule that searching a document. If the mode is omitted, the text is tokenized by the `ADD` mode.

The default mode is `ADD`.

Here is an example to the `ADD` mode.

Execution example:

    tokenize TokenBigram "Fulltext Search" --mode ADD
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "Fu"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "ul"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "ll"
    #     },
    #     {
    #       "position": 3,
    #       "force_prefix": false,
    #       "value": "lt"
    #     },
    #     {
    #       "position": 4,
    #       "force_prefix": false,
    #       "value": "te"
    #     },
    #     {
    #       "position": 5,
    #       "force_prefix": false,
    #       "value": "ex"
    #     },
    #     {
    #       "position": 6,
    #       "force_prefix": false,
    #       "value": "xt"
    #     },
    #     {
    #       "position": 7,
    #       "force_prefix": false,
    #       "value": "t "
    #     },
    #     {
    #       "position": 8,
    #       "force_prefix": false,
    #       "value": " S"
    #     },
    #     {
    #       "position": 9,
    #       "force_prefix": false,
    #       "value": "Se"
    #     },
    #     {
    #       "position": 10,
    #       "force_prefix": false,
    #       "value": "ea"
    #     },
    #     {
    #       "position": 11,
    #       "force_prefix": false,
    #       "value": "ar"
    #     },
    #     {
    #       "position": 12,
    #       "force_prefix": false,
    #       "value": "rc"
    #     },
    #     {
    #       "position": 13,
    #       "force_prefix": false,
    #       "value": "ch"
    #     },
    #     {
    #       "position": 14,
    #       "force_prefix": false,
    #       "value": "h"
    #     }
    #   ]
    # ]

The last alphabet is tokenized by one character.

Here is an example to the `GET` mode.

Execution example:

    tokenize TokenBigram "Fulltext Search" --mode GET
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     {
    #       "position": 0,
    #       "force_prefix": false,
    #       "value": "Fu"
    #     },
    #     {
    #       "position": 1,
    #       "force_prefix": false,
    #       "value": "ul"
    #     },
    #     {
    #       "position": 2,
    #       "force_prefix": false,
    #       "value": "ll"
    #     },
    #     {
    #       "position": 3,
    #       "force_prefix": false,
    #       "value": "lt"
    #     },
    #     {
    #       "position": 4,
    #       "force_prefix": false,
    #       "value": "te"
    #     },
    #     {
    #       "position": 5,
    #       "force_prefix": false,
    #       "value": "ex"
    #     },
    #     {
    #       "position": 6,
    #       "force_prefix": false,
    #       "value": "xt"
    #     },
    #     {
    #       "position": 7,
    #       "force_prefix": false,
    #       "value": "t "
    #     },
    #     {
    #       "position": 8,
    #       "force_prefix": false,
    #       "value": " S"
    #     },
    #     {
    #       "position": 9,
    #       "force_prefix": false,
    #       "value": "Se"
    #     },
    #     {
    #       "position": 10,
    #       "force_prefix": false,
    #       "value": "ea"
    #     },
    #     {
    #       "position": 11,
    #       "force_prefix": false,
    #       "value": "ar"
    #     },
    #     {
    #       "position": 12,
    #       "force_prefix": false,
    #       "value": "rc"
    #     },
    #     {
    #       "position": 13,
    #       "force_prefix": false,
    #       "value": "ch"
    #     }
    #   ]
    # ]

The last alphabet is tokenized by two characters.

#### 7.3.44.4.2.4. `token_filters`

Specifies the token filter names. `tokenize` command uses the tokenizer that is named `token_filters`.

See Token filters about token filters.

## 7.3.44.5. Return value

`tokenize` command returns tokenized tokens. Each token has some attributes except token itself. The attributes will be increased in the feature:

    [HEADER, tokens]

`HEADER`

> See Output format about `HEADER`.

`tokens`

> `tokens` is an array of token. Token is an object that has the following attributes.

> Name | Description
> --- | ---
> `value` | Token itself.
> `position` | The N-th token.

## 7.3.44.6. See also

- Tokenizers

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