# Regular expressions

## Faker Configuration

* **Pattern**: Enter the regular expression pattern to generate the data. For example, `[a-z0-5]{10}` generates a 10-character string consisting of lowercase letters and digits from 0 to 5. Click on `...` button to display the Regex Expression Editor.
* **Add Suffix**: Enter any additional suffix to append to the generated data (optional).
* **Replace only if Non-Null**: Check this box to ensure that the faker only replaces non-null values in the column. If unchecked, it will replace all values, including nulls.

![](https://3044017923-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FBjc0HP8yeHnYIQ2fJ0Ib%2Fuploads%2FRpV46Q0XDi1ZRXzEUEQN%2Fimage.png?alt=media\&token=fe8e7dca-dc7c-4c09-a429-2349d322ca23)

<div align="left"><figure><img src="https://3044017923-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FBjc0HP8yeHnYIQ2fJ0Ib%2Fuploads%2FG5e8o20UBZjpJFP4Bpdz%2Fimage.png?alt=media&#x26;token=b1d6e201-b759-419e-9db3-755025f9f06c" alt=""><figcaption></figcaption></figure></div>

## Example

The regular expression "\[a-z0-5]{10}" specifies a pattern that matches any sequence of 10 characters which are either lowercase letters between 'a' and 'z' or digits between '0' and '5'. The curly braces { } indicate that the preceding character set \[a-z0-5] should be matched exactly 10 times.

![](https://3044017923-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FBjc0HP8yeHnYIQ2fJ0Ib%2Fuploads%2F1BN7yZYwFjIqiVHkFWr3%2Fimage.png?alt=media\&token=692dffb7-fe29-4fab-9028-13cb2d4ca500)