Custom Analyzers: Character filters

Overview

A character filter is a component of an analyzer that receives the original text as a stream of characters and transforms the stream by adding, removing, or changing characters. It is used to modify or clean up the input text by removing special characters, converting cases, or replacing specific characters or sequences of characters.

There are three types of character filters available in Elasticsearch:

• The HTML strip filter

• The mapping character filter

• The pattern-replace filter