Sure thing. To keep it simple suppose I have just a two dimensional array (time,output): [(1,2),(2,3),(3,4)] I would like to look at all values of output for which, for example time==2.
My actual application has a six dimensional array and I'd like to look at the contents using one or more of the first three dimensions. Many thanks, Ted On 01/30/2012 10:50 AM, Zachary Pincus wrote: > Ted, can you clarify what you're asking for? Maybe give a trivial example of > an array and the desired output? > > I'm pretty sure this is a slicing question though: >> If I have a three dimensional array a=(x,y,z), can I look at the values of z >> given particular values for x and y? > Given that element values are scalars in this case, and indices are (x,y,z) > triples, it seems likely that looking for "values of z" given an (x,y) pair > is an slicing-by-index question, no? > > For indexing-by-value, "fancy indexing" with boolean masks is usually the way > to go... again, Ted (or Chao), if you can describe your indexing needs in a > bit more detail, it's often easy to find a compact slicing and/or > fancy-indexing strategy that works well and reasonably efficiently. > > Zach > > > > On Jan 30, 2012, at 10:33 AM, Chao YUE wrote: > >> he is not asking for slicing. he is asking for how to index array by element >> value but not element index. >> >> 2012/1/30 Zachary Pincus <zachary.pin...@yale.edu> >> a[x,y,:] >> >> Read the slicing part of the tutorial: >> http://www.scipy.org/Tentative_NumPy_Tutorial >> (section 1.6) >> >> And the documentation: >> http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html >> >> >> >> On Jan 30, 2012, at 10:25 AM, Ted To wrote: >> >>> Hi, >>> >>> Is there some straightforward way to access an array by values across a >>> subset of its dimensions? For example, if I have a three dimensional >>> array a=(x,y,z), can I look at the values of z given particular values >>> for x and y? >>> >>> Thanks, >>> Ted >>> _______________________________________________ >>> NumPy-Discussion mailing list >>> NumPy-Discussion@scipy.org >>> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> >> >> >> -- >> *********************************************************************************** >> Chao YUE >> Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL) >> UMR 1572 CEA-CNRS-UVSQ >> Batiment 712 - Pe 119 >> 91191 GIF Sur YVETTE Cedex >> Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16 >> ************************************************************************************ >> >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> http://mail.scipy.org/mailman/listinfo/numpy-discussion > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
