---
title: Regex functions
description: Scalar functions for regular expressions
image: https://developers.cloudflare.com/dev-products-preview.png
---

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# Regex functions

_Cloudflare Pipelines scalar function implementations are based on [Apache DataFusion ↗](https://arrow.apache.org/datafusion/) (via [Arroyo ↗](https://www.arroyo.dev/)) and these docs are derived from the DataFusion function reference._

Cloudflare Pipelines uses a [PCRE-like ↗](https://en.wikibooks.org/wiki/Regular%5FExpressions/Perl-Compatible%5FRegular%5FExpressions)regular expression [syntax ↗](https://docs.rs/regex/latest/regex/#syntax) (minus support for several features including look-around and backreferences).

## `regexp_like`

Returns true if a [regular expression ↗](https://docs.rs/regex/latest/regex/#syntax) has at least one match in a string, false otherwise.

```
regexp_like(str, regexp[, flags])
```

**Arguments**

* **str**: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
* **regexp**: Regular expression to test against the string expression. Can be a constant, column, or function.
* **flags**: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:  
  * **i**: case-insensitive: letters match both upper and lower case
  * **m**: multi-line mode: ^ and $ match begin/end of line
  * **s**: allow . to match \\n
  * **R**: enables CRLF mode: when multi-line mode is enabled, \\r\\n is used
  * **U**: swap the meaning of x\* and x\*?

**Example**

```
select regexp_like('Köln', '[a-zA-Z]ö[a-zA-Z]{2}');+--------------------------------------------------------+| regexp_like(Utf8("Köln"),Utf8("[a-zA-Z]ö[a-zA-Z]{2}")) |+--------------------------------------------------------+| true                                                   |+--------------------------------------------------------+SELECT regexp_like('aBc', '(b|d)', 'i');+--------------------------------------------------+| regexp_like(Utf8("aBc"),Utf8("(b|d)"),Utf8("i")) |+--------------------------------------------------+| true                                             |+--------------------------------------------------+
```

Additional examples can be found [here ↗](https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/regexp.rs)

## `regexp_match`

Returns a list of [regular expression ↗](https://docs.rs/regex/latest/regex/#syntax) matches in a string.

```
regexp_match(str, regexp[, flags])
```

**Arguments**

* **str**: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
* **regexp**: Regular expression to match against. Can be a constant, column, or function.
* **flags**: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:  
  * **i**: case-insensitive: letters match both upper and lower case
  * **m**: multi-line mode: ^ and $ match begin/end of line
  * **s**: allow . to match \\n
  * **R**: enables CRLF mode: when multi-line mode is enabled, \\r\\n is used
  * **U**: swap the meaning of x\* and x\*?

**Example**

```
select regexp_match('Köln', '[a-zA-Z]ö[a-zA-Z]{2}');+---------------------------------------------------------+| regexp_match(Utf8("Köln"),Utf8("[a-zA-Z]ö[a-zA-Z]{2}")) |+---------------------------------------------------------+| [Köln]                                                  |+---------------------------------------------------------+SELECT regexp_match('aBc', '(b|d)', 'i');+---------------------------------------------------+| regexp_match(Utf8("aBc"),Utf8("(b|d)"),Utf8("i")) |+---------------------------------------------------+| [B]                                               |+---------------------------------------------------+
```

Additional examples can be found [here ↗](https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/regexp.rs)

## `regexp_replace`

Replaces substrings in a string that match a [regular expression ↗](https://docs.rs/regex/latest/regex/#syntax).

```
regexp_replace(str, regexp, replacement[, flags])
```

**Arguments**

* **str**: String expression to operate on. Can be a constant, column, or function, and any combination of string operators.
* **regexp**: Regular expression to match against. Can be a constant, column, or function.
* **replacement**: Replacement string expression. Can be a constant, column, or function, and any combination of string operators.
* **flags**: Optional regular expression flags that control the behavior of the regular expression. The following flags are supported:  
  * **g**: (global) Search globally and don't return after the first match
  * **i**: case-insensitive: letters match both upper and lower case
  * **m**: multi-line mode: ^ and $ match begin/end of line
  * **s**: allow . to match \\n
  * **R**: enables CRLF mode: when multi-line mode is enabled, \\r\\n is used
  * **U**: swap the meaning of x\* and x\*?

**Example**

```
SELECT regexp_replace('foobarbaz', 'b(..)', 'X\\1Y', 'g');+------------------------------------------------------------------------+| regexp_replace(Utf8("foobarbaz"),Utf8("b(..)"),Utf8("X\1Y"),Utf8("g")) |+------------------------------------------------------------------------+| fooXarYXazY                                                            |+------------------------------------------------------------------------+SELECT regexp_replace('aBc', '(b|d)', 'Ab\\1a', 'i');+-------------------------------------------------------------------+| regexp_replace(Utf8("aBc"),Utf8("(b|d)"),Utf8("Ab\1a"),Utf8("i")) |+-------------------------------------------------------------------+| aAbBac                                                            |+-------------------------------------------------------------------+
```

Additional examples can be found [here ↗](https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/regexp.rs)

## `position`

Returns the position of `substr` in `origstr` (counting from 1). If `substr` does not appear in `origstr`, return 0.

```
position(substr in origstr)
```

**Arguments**

* **substr**: The pattern string.
* **origstr**: The model string.

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