> 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-v8/functions/string/tolower-string-str.md).

# ToLower(String str)

| Name                     | *ToLower*                                                 |
| ------------------------ | --------------------------------------------------------- |
| Applicable To (DataType) | String                                                    |
| Purpose                  | To convert the string argument into lowercase characters. |
| Description              | Converts the string argument into lowercase characters.   |
| Return Type              | String                                                    |
| Syntax                   | str \[System.String] – string which will be converted.    |

![properties](https://github.com/astera-software/Astera_Data_Stack_v9/blob/main/.gitbook/assets/properties%20\(5\).png)

## Example

In this example, we have a customer’s data in which we want to convert the *CustomerID* information into lower case. Map the *CustomerID* to the *str* data field under the *Input* node inside the function transformation object.

![dataflow](https://github.com/astera-software/Astera_Data_Stack_v9/blob/main/.gitbook/assets/dataflow%20\(6\).png)

Right-click on the header of function transformation object and select *Preview Output*. You can see that all the *CustomerIDs* have been converted into lower case.

![output](https://github.com/astera-software/Astera_Data_Stack_v9/blob/main/.gitbook/assets/output%20\(4\).png)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://documentation.astera.com/astera-data-stack-v8/functions/string/tolower-string-str.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.