[SciPy-User] Suggestion for numpy.genfromtxt documentation

Skipper Seabold jsseabold@gmail....
Wed Oct 7 10:52:29 CDT 2009


On Wed, Oct 7, 2009 at 11:25 AM, Dharhas Pothina
<Dharhas.Pothina@twdb.state.tx.us> wrote:
> Hi,
>
> It took me a while and a lot of trial and error to work out why this didn't work as expected.
>
> data = np.genfromtxt(fname,usecols=(2,3,4),names='x,y,z')
>
> this command works and does not return any warnings or errors, but returns an numpy array with no field names. If you use:
>
> data = np.genfromtxt(fname,usecols=(2,3,4),dtype=None,names='x,y,z')
>
> then the command does what I expect it to and returns a structured numpy array with field names. So essentially, the 'names' argument doesn't not work unless you also specify the 'dtype' argument.
>
> I think, it would be less confusing to new users to either have this explicitly mentioned in the documentation string for the genfromtxt 'names' argument or to have the function default to 'dtype=None'  if the 'names' argument is specified without specifying the 'dtype' argument.
>
> - dharhas

I came across this behavior recently and agree with you.  There is a
patch in the works for this.

See this thread: http://thread.gmane.org/gmane.comp.python.numeric.general/33479

And this ticket: http://projects.scipy.org/numpy/ticket/1252

Cheers,

Skipper


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