> For the complete documentation index, see [llms.txt](https://docs.stackai.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.stackai.com/stackai-tools/data-and-code/regex-extract.md).

# Regex Extract

Find text that follows a defined pattern, such as a reference number or a date format. Regular expressions describe the pattern to match; they do not interpret the meaning of the text.

## Extract matching text

1. Pass the source text to **Content to extract from**.
2. Enter the pattern in **Regular expression**. Match the required format as narrowly as possible.
3. Run the tool. Inspect **Result** with text that contains a match and text that contains no match before using it downstream.

**Result:** **Result** is a text representation of the list of matches. It is not a JSON array.

## Behavior and troubleshooting

A broad pattern can match unrelated text. Parentheses used for capture groups can affect the returned matches. Backslashes may need escaping when a pattern is supplied through JSON. Use a JSON extraction tool for structured JSON fields.

## Inputs

| Field                              | Parameter    | Description                                          |
| ---------------------------------- | ------------ | ---------------------------------------------------- |
| Content to extract from (required) | `content`    | The content to extract from                          |
| Regular expression (required)      | `expression` | The regular expression to use to extract the content |

## Outputs

| Field  | Parameter | Description                        |
| ------ | --------- | ---------------------------------- |
| Result | `result`  | The result of the regex extraction |

## Related guidance

[Data Types, Lists, Missing Values, and Empty Results](/technical-reference/workflow-execution/data-types-lists-missing-values-and-empty-results.md)


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