# Matches Check whether a string matches a regular expression. This function returns a Boolean. ## Related examples * [Returning values based on regular expressions matches](https://help.qlik.com/talend/en-US/data-mapper-functions-reference-guide/8.0/returning-values-based-on-regular-expressions-matches) ## Arguments | Input Value | Specify the value to check. | | --- | --- | ## Properties | Regex Value | Specify the regular expression to use.

The syntax is based on the W3 XML Schema regular expressions syntax. It supports:

^ and $ to match respectively the start and end of the input string or the start and end of each line in the input.
Captured sub-expressions.
Back-references.
Unicode block names.

For more information, see the [W3C documentation](https://www.w3.org/TR/xpath-functions-31/#regex-syntax).

This property is also available as
an argument. If you specify both, the argument value is used and
the property value is ignored. | | --- | --- | | Case sensitive | Select this check box if you want to match text with a specific
case. | | Ignore white space | Select this check box if you want to ignore white space
characters in the regular expression. This can be useful if you are
creating a long regular expression and want to split it over several
lines to make it more readable.

For example, with
the Ignore white space
option enabled, the regular expression Main Street would not match the following
value:

```
123 Main Street
Traverse City, MI 49684
```

You
would need to use Main\sStreet
to match it. | | Single Line | Select this check box if you want the input value to be processed as a
single line, even if it contains line breaks. This means that:

The . character matches any character, including line breaks.
The ^ character only matches the beginning of the whole string and the $ character only matches the end of the whole string.

For example, with the Single Line option
enabled, the regular expression Street$\n^Traverse would
not match the following value:

```
123 Main Street
Traverse City, MI 49684
```

However,
Street\nTraverse or Street.\*Traverse
would match. |