Pau Gargallo wrote: > On 6/21/06, Travis Oliphant <[EMAIL PROTECTED]> wrote: > >> Johannes Loehnert wrote: >> >>> Hi, >>> >>> >>> >>>> I'm not sure why bool arrays cannot be used as indices. >>>> The "natural" solution to the original problem seemed to be: >>>> M[:,V>0] >>>> but this is not allowed. >>>> >>>> >>> I started a thread on this earlier this year. Try searching the archive for >>> "boolean indexing" (if it comes back online somewhen). >>> >>> Travis had some reason for not implementing this, but unfortunately I do not >>> remember what it was. The corresponding message might still linger on my >>> home >>> >>> PC, which I can access this evening.... >>> >>> >> I suspect my reason was just not being sure if it could be explained >> consistently. But, after seeing this come up again. I decided it was >> easy enough to implement. >> >> So, in SVN NumPy, you will be able to do >> >> a[:,V>0] >> a[V>0,:] >> >> The V>0 will be replaced with integer arrays as if nonzero(V>0) had been >> called. >> >> > > does it work for a[<boolean>,<boolean>] ? > Sure, it will work. Basically all boolean arrays will be interpreted as nonzero(V>0), everywhere. > what about a[ix_( nonzero(<boolean>), nonzero(<boolean>) )] ? > > maybe the <boolean> to nonzero(<boolean>) conversion would be more > coherently done by the ix_ function than by the [] > > I've just added support for <boolean> inside ix_ so that the nonzero will be done automatically as well.
So a[ix_(<boolean>,<boolean>)] will give the cross-product selection. -Travis All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642 _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion