# output_format()


Use *name* as the dataset output format for a `with` block.


Usage

``` python
output_format(name)
```


The previous format is restored on exit, including when the block raises. The switch is context-local.


## Parameters


`name: OutputFormat`  
The format to use inside the block: `"arrow"`, `"polars"` or `"pandas"`.


## Raises


`ValueError`  
If *name* is not `"arrow"`, `"polars"` or `"pandas"`.


## Examples

``` python
>>> with pharmadata.output_format("pandas"):
...     df = pharmadata.pharmaverseadam.adsl
...     type(df).__module__.split(".")[0]
'pandas'
>>> pharmadata.get_output_format()  # restored on exit
'polars'
```