Erin Sheldon wrote: > On 11/12/06, Tim Hochberg <[EMAIL PROTECTED]> wrote: > >> I haven't been following this too closely, but if you need to transpose >> your data without converting all to one type, I can think of a couple of >> different approaches: >> >> 1. zip(*yourlist) >> 2. numpy.transpose(numpy.array(yourlist, dtype=object) >> >> I haven't tested them though (particularly the second one), so caveat >> emptor, etc, etc. >> > > Its not that I want to transpose data. > > I'm trying to convert the output of a pgdb postgres query into > an array with fields and types corresponding to the columns > I have selected. The problem is pgdb does not return a list > of tuples as it should according to DB 2.0, but instead > a list of lists. So numpy.array(lol, dtype=) fails, and so will your > solution #2. In that case, I suggest just using a list comprehension or map, [tuple(x) for x in lol] for example.
> I don't want to copy the data more than once > obviously, so I'm looking for a way to call array() with a lists > of lists. > It's probably pointless to worry about his. You are already allocating 5*N python objects (all those Python floats and integers as well as the lists themselves). I believe the list comprehension above is only going to allocate an additional N objects (the new tuples). Admittedly, the objects aren't all the same size, but in this case they are close enough that I doubt it'll matter. -tim ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion