Advanced Elasticsearch 7.0

The pattern_replace filter

You can specify a regular expression (for more information, you can refer to https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html) to match a sequence of characters. When the input string has such a sequence, the original value will be substituted by the replacement string. To define a pattern_replace character filter, you need to specify three parameters:

• The Java regular expression (pattern)
• The replacement string (replacement)
• The Java regular expression flag (flags)

Let's take a look at an example of how to replace the input text, 7.0, with v7. We will apply all three character filters: html_strip, mapping, and pattern_replace. We write a regular expression matching pattern, (\\d+).(\\d+) ...