# SubString (NoOfChars)

| **Name**    | ***Substring***                                                                                                                                                                                                  |
| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Syntax      | Substring (String str, Integer startAt, Integer noOfChars)                                                                                                                                                       |
| Purpose     | To get part of the string starting at startAt, and of length, noOfChars                                                                                                                                          |
| Description | Returns a string of characters from a string beginning at startAt and of maximum length equal to noOfChars. If startAt is greater than or equal to string length, empty string is returned.                      |
| Return Type | String                                                                                                                                                                                                           |
| Parameters  | <p>str \[System.String] – String whose part will be returned</p><p>startAt \[System.Int64] – Start position of the string to return</p><p>noOfChars \[System.Int64] – Maximum number of characters to return</p> |

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/5Ry1VFk0A8dkbio5bjwk/0.png)

**Example**

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

Where,

*str*: ABCDEFGHI

*startAt =* 2

*noOfChars* = 4

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/CozuqH2NURWXSp6jUeuW/1.png)

Right-click on the function transformation object and select *Preview Output.* You can see that Astera Data Stack has returned a part of the string, starting at position *startAt*, and of length, *noOfChars.*

![](https://content.gitbook.com/content/zEifS4h8yurLAAwiGNX2/blobs/1rgtC8tRUaYBAJfOIw6J/2.png)