> For the complete documentation index, see [llms.txt](https://docs.pentaho.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.pentaho.com/pdia-data-integration/10.2-data-integration/pdi-transformation-steps-reference-overview/regex-evaluation.md).

# Regex Evaluation

The Regex evaluation step matches the strings of an input field against a text pattern you define with a regular expression (regex). This step uses the `java.util.regex` package. The syntax for creating the regular expressions used by this step is defined in the [java.util.regex.Pattern javadoc](https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html).

You can use this step to parse a complex string of text and create new fields out of the input field with capture groups (defined by parentheses). For example, if you have an input field containing an author's name in quotes and the number of posts made by them, you can create two new fields in your transformation - one for the name, and one for the number of posts as shown below:

Text to parse:

```
"Author, Ann" - 53 posts
```

Regex to create two capture groups:

```
^"([^"]*)" - (\d*) posts$
```

The resulting field values are: Ann and 53.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.pentaho.com/pdia-data-integration/10.2-data-integration/pdi-transformation-steps-reference-overview/regex-evaluation.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.