# Regex

A reged (regular expression) can be used to specify a match pattern in text.

_(since v3.0.0)_

A `regex` can be created by casting from a string.

The following examples all return `true`.

```surql
-- Either 'a' or 'b'
<regex> "a|b" = "a";

-- Either color or colour
<regex> "col(o|ou)r" = "colour";

-- Case-insensitive match on English color, colour, or French couleur
<regex> "((?i)col(o|ou)r|couleur)" = "COULEUR";
```

While `regex` was added as a standalone type in version 2.3.0, regex matching has always been available via the [`string::matches()`](/docs/reference/query-language/functions/database-functions/string.md#stringmatches) function.

```surql
string::matches("a", "a|b");
string::matches("colour", "col(o|ou)r");
string::matches("COULEUR", "((?i)col(o|ou)r|couleur)");
```