> For the complete documentation index, see [llms.txt](https://documentation.astera.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.astera.com/astera-data-stack-v10/functions/regular-expressions/ismatchregex-startat.md).
# IsMatchRegEx (StartAt)
| **Name** | ***IsMatchRegEx*** |
| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Syntax | IsMatchRegEx (String pattern, String str, Integer startAt) |
| Purpose | To return true if the regular expression found a match in the string. Otherwise, returns false. It also considers the starting position. |
| Description | Indicates whether the regular expression finds a match in a specified input string value at the specified integer position. |
| Return Type | Boolean |
| Parameters | pattern \[System.String] – Regular expression pattern to match
str \[System.String] – String to search for a match
startAt \[System.Int64] – The character position from which to start the search
|
**Example**
In this example, we will pass the required parameters to the function transformation object using a *Variables* object.
Where,
*pattern* = {x,y}
*str* = 1234{x,y}
*startAt* = 4
In the output window, you can see that Astera has returned “True”, as the specified string matches the specified pattern value, from the specified start position.
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