# Regex extract

> Supported in: Batch, Faster, Streaming

Extracts the specified group from a regex. Returns empty string when no match is found.

**Expression categories:** Regex, String

## Declared arguments

* **Expression:** The expression to extract from.<br>*Expression\<String>*
* **Group:** The group to extract from the regex match.<br>*Literal\<Integer>*
* **Pattern:** The regex pattern to match.<br>*Expression\<String>*

**Output type:** *String*

## Examples

### Example 1: Base case

**Description:** Extract the first two initials from the first match.

**Argument values:**

* **Expression:** MT-112, XB-967
* **Group:** 1
* **Pattern:** (\w\w)(-)

**Output:** MT

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### Example 2: Base case

**Argument values:**

* **Expression:** MT-112, XB-967
* **Group:** 0
* **Pattern:** NOT\_FOUND

**Output:** *empty string*

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### Example 3: Base case

**Argument values:**

* **Expression:** zzzzhello hellozzzz
* **Group:** 1
* **Pattern:** (hello) \1

**Output:** hello

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### Example 4: Base case

**Argument values:**

* **Expression:** helloworld
* **Group:** 1
* **Pattern:** (\w+)(?=world)

**Output:** hello

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### Example 5: Null case

**Description:** Null inputs give null outputs.

**Argument values:**

* **Expression:** *null*
* **Group:** 1
* **Pattern:** (\w\w)(-)

**Output:** *null*

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