OpenSearch/docs/reference/analysis/tokenizers/simplepatternsplit-tokenizer.asciidoc
Andy Bristol 48696ab544 expose simple pattern tokenizers (#25159)
Expose the experimental simplepattern and 
simplepatternsplit tokenizers in the common 
analysis plugin. They provide tokenization based 
on regular expressions, using Lucene's 
deterministic regex implementation that is usually 
faster than Java's and has protections against 
creating too-deep stacks during matching.

Both have a not-very-useful default pattern of the 
empty string because all tokenizer factories must 
be able to be instantiated at index creation time. 
They should always be configured by the user 
in practice.
2017-06-13 12:46:59 -07:00

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[[analysis-simplepatternsplit-tokenizer]]
=== Simple Pattern Split Tokenizer
experimental[]
The `simplepatternsplit` tokenizer uses a regular expression to split the
input into terms at pattern matches. The set of regular expression features it
supports is more limited than the <<analysis-pattern-tokenizer,`pattern`>>
tokenizer, but the tokenization is generally faster.
This tokenizer does not produce terms from the matches themselves. To produce
terms from matches using patterns in the same restricted regular expression
subset, see the <<analysis-simplepattern-tokenizer,`simplepattern`>>
tokenizer.
This tokenizer uses {lucene-core-javadoc}/org/apache/lucene/util/automaton/RegExp.html[Lucene regular expressions].
For an explanation of the supported features and syntax, see <<regexp-syntax,Regular Expression Syntax>>.
The default pattern is the empty string, which produces one term containing the
full input. This tokenizer should always be configured with a non-default
pattern.
[float]
=== Configuration
The `simplepatternsplit` tokenizer accepts the following parameters:
[horizontal]
`pattern`::
A {lucene-core-javadoc}/org/apache/lucene/util/automaton/RegExp.html[Lucene regular expression], defaults to the empty string.
[float]
=== Example configuration
This example configures the `simplepatternsplit` tokenizer to split the input
text on underscores.
[source,js]
----------------------------
PUT my_index
{
"settings": {
"analysis": {
"analyzer": {
"my_analyzer": {
"tokenizer": "my_tokenizer"
}
},
"tokenizer": {
"my_tokenizer": {
"type": "simplepatternsplit",
"pattern": "_"
}
}
}
}
}
POST my_index/_analyze
{
"analyzer": "my_analyzer",
"text": "an_underscored_phrase"
}
----------------------------
// CONSOLE
/////////////////////
[source,js]
----------------------------
{
"tokens" : [
{
"token" : "an",
"start_offset" : 0,
"end_offset" : 2,
"type" : "word",
"position" : 0
},
{
"token" : "underscored",
"start_offset" : 3,
"end_offset" : 14,
"type" : "word",
"position" : 1
},
{
"token" : "phrase",
"start_offset" : 15,
"end_offset" : 21,
"type" : "word",
"position" : 2
}
]
}
----------------------------
// TESTRESPONSE
/////////////////////
The above example produces these terms:
[source,text]
---------------------------
[ an, underscored, phrase ]
---------------------------