> My preferred way of implementing that would be a generic, > stateless transformer class that just runs a function on X in > transform and returns the result.
I think this is useful anyway, and an effective but not ideal solution for this use-case. Here that makes a lot of overhead for what is really a straightforward application. On 28 February 2014 12:37, Michael Kneier <michael.kne...@gmail.com> wrote: > Thanks for the great replies. As Lars rightly points out, I could define a > custom transform to accomplish the combining. > > I do think that this could be more intuitively implemented (or at least > built in to FeatureUnion), and I'd like pitch in on the > https://github.com/scikit-learn/scikit-learn/issues/2034. I will take a > closer look this weekend. > > Thanks, > Mike > > > On Thu, Feb 27, 2014 at 3:11 PM, Lars Buitinck <larsm...@gmail.com> wrote: >> >> 2014-02-27 23:37 GMT+01:00 Joel Nothman <joel.noth...@gmail.com>: >> > I think it would be nice if the FeatureUnion makes it easy to extract >> > only certain parts of the input for each transformer. >> > https://github.com/scikit-learn/scikit-learn/issues/2034 intends to >> > cover this issue, but we haven't resolved a clean API. >> > >> > Suggestions are welcome! >> >> I hope you don't mind me replying here: I think this can be resolved >> by custom transformers that pass through a user-specified set of >> columns. My preferred way of implementing that would be a generic, >> stateless transformer class that just runs a function on X in >> transform and returns the result. If this transformer doesn't do input >> validation, you could make a union >> >> make_pipeline(FunctionTransformer(extract_description_terms), >> TfidfTransformer()) >> ∪ >> make_pipeline(FunctionTransformer(extract_portrait_pixels), PCA()) >> >> and feed this filenames, or dicts, or whatever. The original problem >> of letting though only some columns is then >> >> def even_columns(X, *args): >> X = np.asarray(X) >> return X[:, ::2] >> >> FunctionTransformer(even_columns) >> >> And of course, these things are more generally useful for inserting a >> simple function in the middle of a pipeline. >> >> >> ------------------------------------------------------------------------------ >> Flow-based real-time traffic analytics software. Cisco certified tool. >> Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer >> Customize your own dashboards, set traffic alerts and generate reports. >> Network behavioral analysis & security monitoring. All-in-one tool. >> >> http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk >> _______________________________________________ >> Scikit-learn-general mailing list >> Scikit-learn-general@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/scikit-learn-general > > > > ------------------------------------------------------------------------------ > Flow-based real-time traffic analytics software. Cisco certified tool. > Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer > Customize your own dashboards, set traffic alerts and generate reports. > Network behavioral analysis & security monitoring. All-in-one tool. > http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk > _______________________________________________ > Scikit-learn-general mailing list > Scikit-learn-general@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/scikit-learn-general > ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk _______________________________________________ Scikit-learn-general mailing list Scikit-learn-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/scikit-learn-general
