# IsAlpha

| **Name**    | ***IsAlpha***                                                                                                                                                                                              |
| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Syntax      | IsAlpha (String str)                                                                                                                                                                                       |
| Purpose     | To check whether the specified character within a string, in the specified index position, is alphabetical.                                                                                                |
| Description | Checks whether specified character is alphabetic                                                                                                                                                           |
| Return Type | Boolean                                                                                                                                                                                                    |
| Parameters  | <p>str \[System.String] – String containing the character to test</p><p>index \[System.Int32] – Numerical position of the character in the string to test. If not specified, index is presumed to be 0</p> |

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/CoiEaexTw2HpM7n9oXI1/0.png)

**Example**

In this example, we are passing the required parameters to the function transformation object using a *Variables* object.

Where,

*str* = 1a2b3c4d

*index* = 1

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/HOzmCMSCLQvXKx0gn9tQ/1.png)

Right-click on the function transformation object and select *Preview Output.* You can see that Astera Data Stack has returned “True”, as the character in the specified numerical position is alphabetical.

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/2Mr9BUSuVXtrYmCjpCfh/2.png)

Conversely, if we replace the *index* value with “0”, the output value will return the boolean value, “False”, as shown below:

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/l6hVWttpInlV6WcRsdE4/3.png)