Mailman 3 August 2021 - Pandas-dev

Re: [Pandas-dev] A case for a simplified (non-consolidating) BlockManager with 1D blocks
by Brock Mendel Dec. 17, 2021

Dec. 17, 2021

> We actually *have* prototypes: the prototype of the split-policy discussed AFAICT that is a 5 year old branch. Is there a version of this based off of master that you can show asv results for? > Also, if performance is in the end the decisive criterion, I repeat my earlier remark in this thread: we need to be clearer about what we want / expect. In principle, this is pretty much exactly what the asvs are supposed to represent. ---- You have demonstrated that you are willing to repeat yourself more than I am, to the point that I find pandas interactions more frustrating than fulfilling. I'm going to step away for a little while. On Thu, Jun 11, 2020 at 1:29 PM Daniel Scott <scottdaniel539(a)yahoo.com> wrote: > > > Sent from Yahoo Mail on Android > <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_And…> > > On Thu, Jun 11, 2020 at 3:10 PM, Joris Van den Bossche > <jorisvandenbossche(a)gmail.com> wrote: > _______________________________________________ > Pandas-dev mailing list > Pandas-dev(a)python.org > https://mail.python.org/mailman/listinfo/pandas-dev > >

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Proposal for consistent, clear copy/view semantics in pandas with Copy-on-Write
by Joris Van den Bossche Oct. 11, 2021

Oct. 11, 2021

*(a.k.a. getting rid of the SettingWithCopyWarning)* Hi all, As you are probably aware, it's not always straightforward to understand the copy or view semantics of indexing methods in pandas. To understand when you get a view and when not, or why you get a SettingWithCopyWarning or how to get rid of it? It's also something that has already been discussed regularly (e.g. the discussion and implementation from 2015 started by Nick Eubank at gh-10954 <https://github.com/pandas-dev/pandas/issues/10954>). Last year, we again started to discuss this, which is tracked at https://github.com/pandas-dev/pandas/issues/36195. Based on those discussions, I have a concrete proposal to change the copy/view semantics of pandas. Short summary of the proposal: 1. The result of *any* indexing operation (subsetting a DataFrame or Series in any way) or any method returning a new DataFrame, always *behaves as if it were* a copy in terms of user API. 2. We implement Copy-on-Write. This way, we can actually use views as much as possible under the hood, while ensuring the user API behaves as a copy. This addresses multiple aspects: 1) a clear and consistent user API (a clear rule: *any* subset or returned series/dataframe is *always* a copy of the original, and thus never modifies the original) and 2) improving performance by avoiding excessive copies (eg a chained method workflow would no longer return an actual data copy at each step). Longer version of this proposal: https://docs.google.com/document/d/1ZCQ9mx3LBMy-nhwRl33_jgcvWo9IWdEfxDNQ2th… Proof-of-concept implementation: https://github.com/pandas-dev/pandas/pull/41878 GitHub issue with relevant discussion: https://github.com/pandas-dev/pandas/issues/36195 *Since this would be a change with a large impact on users, I think it is important to get broad feedback on this*. So comments, thoughts, concerns, ideas etc are very welcome (you can comment on the google doc, answer to this email or on the github issue). Best, Joris

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ANN: pandas v1.3.2
by Simon Hawkins Aug. 16, 2021

Aug. 16, 2021

Hi all, I'm pleased to announce the release of pandas v1.3.2. This is a patch release in the 1.3.x series and includes some regression fixes and bug fixes. We recommend that all users upgrade to this version. See the release notes <https://pandas.pydata.org/pandas-docs/version/1.3/whatsnew/v1.3.2.html> for a list of all the changes. The release can be installed from PyPI python -m pip install --upgrade pandas==1.3.2 Or from conda-forge conda install -c conda-forge pandas==1.3.2 Please report any issues with the release on the pandas issue tracker <https://github.com/pandas-dev/pandas/issues>. Thanks to all the contributors who made this release possible.

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August 2021 monthly community meeting (Wednesday August 11, UTC 18:00)
by Joris Van den Bossche Aug. 10, 2021

Aug. 10, 2021

Hi all, A reminder that the next monthly dev call is tomorrow (Wednesday, August 11th) at 18:00 UTC (1 pm Central). Our calendar is at https://pandas.pydata.org/docs/development/meeting.html#calendar to check your local time. All are welcome to attend! Video Call: https://zoom.us/j/96753852910?pwd=OEgwbUkwOE9kejcwOGdLd09TallTdz09 Minutes: https://docs.google.com/document/u/1/d/1tGbTiYORHiSPgVMXawiweGJlBw5dOkVJLY-… Joris

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