ENH: add to cython groupby functions

[jreback]

• shift here and here
• cumsum
• cumprod

[jtratner]

@jreback can I take this? If it's for 0.13 you have some time and I'd be really interested in a chance to dig into more of the Cython internals.

[jreback]

go for it! you will need to add a function template in src/generate_code.py and add the appropriate places in groupby.py

[jtratner]

@jreback cool - thanks :) I'm looking forward to figuring all that out

[jtratner]

@jreback were you thinking this would cover time series shifting too?

[jreback]

yes the index type actually doesn't matter though its based on position shiftting (well the time-series stuff happens at a high level and is just translated to positions to move anyhow)

[jtratner]

@jreback - if it's already translate to positions to move, then that makes
it much simpler. Thanks!

On Tue, Jul 9, 2013 at 7:34 PM, jreback notifications@github.com wrote:

yes the index type actually doesn't matter though its based on position
shiftting (well the time-series stuff happens at a high level and is just
translated to positions to move anyhow)

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Reply to this email directly or view it on GitHubhttps://github.com//issues/4095#issuecomment-20712874
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[jreback]

yep...look at pandas/core/frame/shift....

[jtratner]

I've let this slide... I will try to circle back to this when I have a chance, but if someone else wants to take it go go go