# eval()

{% hint style="warning" %}
The `eval()` function depends on [scalar functions and operators](/scanner/using-scanner-complete-feature-reference/beta-features/scalar-functions-and-operators.md), which are currently in beta and may change in the future.
{% endhint %}

`eval([...col = expression])` runs each `expression` and assigns it to the corresponding `col`.

`expression` supports any composition of [scalar functions and operators](/scanner/using-scanner-complete-feature-reference/beta-features/scalar-functions-and-operators.md).

Currently, scalar expressions can express more data types than table values can. Hence, at assignment, scalar expression values are converted back to table values as such:

* numbers, strings, and null values are preserved
* boolean values are converted to the strings `"true"` and `"false"`
* arrays are converted to a string via JSON serialization

{% hint style="warning" %}
This conversion behavior may change when direct support for these types is added to tables.
{% endhint %}

## Returns

A same table as the input, with additional columns corresponding to the `col`s specified.

## Examples

Get a list of HTTP 502s, converting the elapsed time from milliseconds to seconds.

```python
response.status=502
| eval elapsed_s = request.elapsed_ms / 1000
```


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