`ddof` argument to `stddev`

[MarcoGorelli]

Is your feature request related to a problem?

narwhals

Describe the solution you'd like

daft.col('a').stddev(ddof=1)

Describe alternatives you've considered

something like

            n_rows = expr.count()
            return expr.stddev() * ((n_rows - 1).sqrt() / (n_rows - 1))

but then I wouldn't be able to evaluate that in over context

Additional Context

No response

Would you like to implement a fix?

No

[venkateshdb]

Hey, Will love to work on this.

[desmondcheongzx]

Hey @venkateshdb, just saw that you left a comment. Feel free to knock this out!

[rchowell]

@venkateshdb still interested? Thanks for taking a look.

[venkateshdb]

Yes, @rchowell I have started working on this. I was stuck on the setup part, but that's resolved now.

[rchowell]

@venkateshdb any updates here? I will re-assign if you are no longer working on this. Thanks!

[venkateshdb]

@rchowell, Almost done with it https://github.com/Eventual-Inc/Daft/pull/4949, got busy with other stuff, will get this done by this weekend.

[malcolmgreaves]

Hi @venkateshdb just checking in, how is it going?

[venkateshdb]

@malcolmgreaves. Sorry for the delay, Got busy with other stuff, will make sure to update the PR this week.