# Replace String

Returns the subject with the specified pattern (or all occurrences of the pattern) either removed or replaced by a replacement string. If no matches are found, returns the original subject.

## Parameters

| Name        | Type    | Description                                                                                                                                                                              | Is Optional |
| ----------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------- |
| source\_col | column  | A string column from which to replace a pattern.                                                                                                                                         |             |
| pattern     | string  | This is the regex pattern that you want to match.                                                                                                                                        |             |
| replacement | string  | This is the value used as a replacement for the pattern.                                                                                                                                 |             |
| alias       | string  | A column name to assign the resulting column.                                                                                                                                            | True        |
| use\_regex  | boolean | Use regex to find string pattern to replace defaults to 'false'; however, regex will be used if any of 'position', 'occurrence', or 'parameters' are provided, regardless of this value. | True        |
| position    | int     | Number of characters from the beginning of the string where the function starts searching for matches. Default: 1                                                                        | True        |
| occurrence  | int     | Specifies which occurrence of the pattern to replace. If 0 is specified, all occurrences are replaced. Default: 0                                                                        | True        |
| parameters  | string  | String of one or more characters that specifies the parameters used for searching for matches. Supported values: c , i , m , e , s. Default: c                                           | True        |

## Example

```python
ds = rasgo.get.dataset(id)

ds2 = ds.replace_string(source_col='WEATHER_DESCRIPTION', pattern='[Dd]rizzle|[Ss]prinkle', replacement='rain')
ds2.preview()

```

## Source Code

{% embed url="<https://github.com/rasgointelligence/RasgoTransforms/blob/main/rasgotransforms/rasgotransforms/transforms/replace_string/replace_string.sql>" %}


---

# Agent Instructions: 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://docs.rasgoml.com/rasgo-docs/rasgo-0.1/all-transforms/replace_string.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.