On Tue, Mar 16, 2010 at 12:08 PM, <[email protected]> wrote: > On Tue, Mar 16, 2010 at 11:52 AM, Skipper Seabold <[email protected]> wrote: >> On Tue, Mar 16, 2010 at 11:46 AM, <[email protected]> wrote: >>> On Tue, Mar 16, 2010 at 11:34 AM, Skipper Seabold <[email protected]> >>> wrote: >>>> On Tue, Mar 16, 2010 at 11:20 AM, Sam Tygier >>>> <[email protected]> wrote: >>>>> Thanks for those responses. >>>>> >>>>> could the dtype pages in the numpy reference link to the basics.rec page >>>>> in the user guide? >>>>> >>>>> there seem to be some gotchas in list within a list notation. >>>>> >>>>> if i have >>>>> a = array([0,0.1,0.2,0.3,0.4]) >>>>> b = array((0,0.1,0.2,0.3,0.4), dtype=[('a','f'), ('b','f'), ('c','f'), >>>>> ('d','f'),('f','f')]) >>>>> >>>>> then >>>>>>>> a[[0,1,4]] >>>>> array([ 0. , 0.1, 0.4]) >>>>>>>> a[[4,1,0]] >>>>> array([ 0.4, 0.1, 0. ]) >>>>> >>>>> but >>>>>>>> b[['a','b','f']] >>>>> (0.0, 0.10000000149011612, 0.40000000596046448) >>>>>>>> b[['f','b','a']] >>>>> (0.0, 0.10000000149011612, 0.40000000596046448) >>>>> >>>>> so i always get the vales back in the original order. is the by design, >>>>> or a bug? >>>>> >>>> >>>> I've been bitten by this before too and asked the same question with >>>> no response. I think it's just a limitation of the design of >>>> structured arrays. >>> >>> It might be by historical design, structured arrays are not really >>> designed for slicing but I think more like sets of variables. >>> >>> But it means it cannot be used directly for the old pattern >>> >>> [arr(name) for name in listofnames] >>> >>> Skipper, Is this subset selection documented anywhere? I only know >>> about it because you showed the example. >>> >> >> Just added it and a link to the cookbook for recarrays. I don't think >> it will show up until the doc wiki changes are applied(?). >> >> http://docs.scipy.org/numpy/docs/numpy.doc.structured_arrays/ > > looks good, together with the cookbook on .view() it almost covers the > FAQs for structured arrays > > I changed "OK to apply:" to Yes so it will get into the docs soon
I also changed the aka to and, to avoid the confusion between recarrays and structured arrays (another FAQ) Structured Arrays (aka Record Arrays) to Structured Arrays (and Record Arrays) Josef > > Josef >> >> Skipper >> _______________________________________________ >> NumPy-Discussion mailing list >> [email protected] >> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> > _______________________________________________ NumPy-Discussion mailing list [email protected] http://mail.scipy.org/mailman/listinfo/numpy-discussion
