# Regex match

> Supported in: Batch, Faster, Streaming

Matches an expression against a regular expression. Regular expression must match the whole string.

**Expression categories:** Regex, String

## Declared arguments

* **Expression:** The expression to match against the regular expression.<br>*Expression\<String>*
* **Regex:** The regular expression to match against.<br>*Expression\<String>*

**Output type:** *Boolean*

## Examples

### Example 1: Base case

**Description:** Regex must match the entire string

**Argument values:**

* **Expression:** (
* **Regex:** abc

**Output:** false

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### Example 2: Base case

**Description:** Regex must match the entire string

**Argument values:**

* **Expression:** abcdefg
* **Regex:** abc

**Output:** false

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### Example 3: Base case

**Description:** You can match regex patterns

**Argument values:**

* **Expression:** abcdefg
* **Regex:** abc?d.+

**Output:** true

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### Example 4: Base case

**Description:** Regex patterns sometimes don't match input strings

**Argument values:**

* **Expression:** abdefg
* **Regex:** ab?d.\*

**Output:** true

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### Example 5: Null case (ANSI mode on)

**Description:** Null patterns propagate to null

**Argument values:**

* **Expression:** foo
* **Regex:** *null*

**Output:** *null*

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### Example 6: Null case (ANSI mode on)

**Description:** Null columns propagate to null

**Argument values:**

* **Expression:** *null*
* **Regex:** ab?d.\*

**Output:** *null*

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### Example 7: Null case (ANSI mode on)

**Argument values:**

* **Expression:** `foo`
* **Regex:** `pattern`

| foo | pattern | **Output** |
| ----- | ----- | ----- |
| foo | ( | false |
| foo | *null* | *null* |
| *null* | foo | *null* |
| *null* | *null* | *null* |

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### Example 8: Null case (ANSI mode off)

**Description:** Null pattern do not match

**Argument values:**

* **Expression:** foo
* **Regex:** *null*

**Output:** false

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### Example 9: Null case (ANSI mode off)

**Description:** Null columns do not match

**Argument values:**

* **Expression:** *null*
* **Regex:** ab?d.\*

**Output:** false

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### Example 10: Null case (ANSI mode off)

**Argument values:**

* **Expression:** `foo`
* **Regex:** `pattern`

| foo | pattern | **Output** |
| ----- | ----- | ----- |
| foo | ( | false |
| foo | *null* | false |
| *null* | foo | false |
| *null* | *null* | false |

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