# IsSubstringOf

| **Name**    | ***IsSubstringOf***                                                                                                 |
| ----------- | ------------------------------------------------------------------------------------------------------------------- |
| Syntax      | IsSubstringOf (String str1, String str2)                                                                            |
| Purpose     | To search specified string for another specified string value and return True if the latter is a substring of str2. |
| Description | Checks whether specified string is a substring of another string value. **Note:** Is case sensitive.                |
| Return Type | Boolean                                                                                                             |
| Parameters  | <p>str1 \[System.String] – String to search for</p><p>str2 \[System.String] – String to search in</p>               |

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/PZcgRVMH85x7pkGlsaWj/0.png)

**Example**

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

Where,

*str1* = llo

*str2* = Hello World

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/3iBvMqfhBC3oYBblywNf/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 *str1* value is a substring of the specified *str2* value.

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/id4kjYIy35JnHOQ2Luj0/2.png)