.. _es-guide-reference-index-modules-analysis-pattern-tokenizer:

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Pattern Tokenizer
=================

A tokenizer of type **pattern** that can flexibly separate text into terms via a regular expression. Accepts the following settings:


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 Setting        Description                                                     
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**pattern**    The regular expression pattern, defaults to **\W+**.             
**flags**      The regular expression flags.                                    
**group**      Which group to extract into tokens. Defaults to **-1** (split).  
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*IMPORTANT*: The regular expression should match the *token separators*, not the tokens themselves.