Thanks guys - I'm happy with the solution for now. FYI, Derek's suggestion doesn't work in numpy 1.5.1 either. For any developers following this thread, I think this might be a nice use case for genfromtxt to handle in future. As a corollary of this problem, I wonder whether there's a human-readable text format for complex numbers that genfromtxt can currently easily parse into a complex array? Having the hard-coded value for the number of columns in the converter and the genfromtxt call goes against the philosophy of the function's ability to form an array of shape matching the input layout.
Gary On Sat, Jun 18, 2011 at 7:24 AM, Derek Homeier <de...@astro.physik.uni-goettingen.de> wrote: > On 17.06.2011, at 11:01PM, Olivier Delalleau wrote: > >>> You were just overdoing it by already creating an array with the converter, >>> this apparently caused genfromtxt to create a structured array from the >>> input (which could be converted back to an ndarray, but that can prove >>> tricky as well) - similar, if you omit the dtype=None. The following >>> >>> cnv = dict.fromkeys(range(4), lambda x: complex(*eval(x))) >>> b = np.genfromtxt(a,converters=cnv, dtype=None, delimiter=18, >>> usecols=range(4)) >>> >>> directly produces a shape(4,4) complex array for me (you may have to apply >>> an .astype(np.complex64) afterwards if so desired). >>> >>> BTW I think this is an interesting enough case of reading non-trivially >>> structured data that it deserves to appear on some examples or cookbook >>> page. >>> >>> HTH, >>> Derek >>> >>> _______________________________________________ >>> NumPy-Discussion mailing list >>> NumPy-Discussion@scipy.org >>> http://mail.scipy.org/mailman/listinfo/numpy-discussion >>> >> I had tried that as well and it doesn't work with numpy 1.4.1 (I get an >> object array). It may have been fixed in a later version. > > OK, I was using the current master from github, but it works in 1.6.0 as > well. I still noticed some differences between loadtxt and genfromtxt > behaviour, e.g. where loadtxt would be able to take a string from the > converter and automatically convert it to a number, whereas in genfromtxt the > converter still had to include the float() or complex()... > > Derek > > _______________________________________________ > 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
