[Numpy-discussion] A bug in loadtxt and how to convert a string array (hex data) to decimal?

frank wang f.yw@hotmail....
Thu Sep 18 17:00:58 CDT 2008


Hi, Ryan,
 
Thank you very much. It solves my problem. I have struggled with this for long time.
 
Frank> Date: Thu, 18 Sep 2008 16:39:47 -0500> From: rmay31@gmail.com> To: numpy-discussion@scipy.org> Subject: Re: [Numpy-discussion] A bug in loadtxt and how to convert a string array (hex data) to decimal?> > frank wang wrote:> > > > > > > > Hi, All,> > > > > > > > > > > > I have found a bug in the loadtxt function. Here is the example. The > > file name is test.txt and contains:> > > > > > "Thist is test"> > > > > > 3FF 3fE> > > > > > 3Ef 3e8> > > > > > 3Df 3d9> > > > > > 3cF 3c7> > > > > > > > > > > > In the Python 2.5.2, I type:> > > > > > > > > > > > test=loadtxt('test.txt',comments='"',dtype='string',converters={0:lambda > > s:int(s,16)})> > > > > > > > > > > > test will contain> > > > > > > > > > > > array([['102', '3fE'],> > > > > > ['100', '3e8'],> > > > > > ['991', '3d9'],> > > > > > ['975', '3c7']],> > > > > > dtype='|S3')> > > > It's because of how numpy handles strings arrays (which I admit I don't > understand very well.) Basically, it's converting the numbers properly, > but truncating them to 3 characters. Try this, which just forces it to > expand to strings 4 characters wide:> test=loadtxt('test.txt',comments='"',dtype='|S4',converters={0:lambda> s:int(s,16)})> > HTH,> > Ryan> > -- > Ryan May> Graduate Research Assistant> School of Meteorology> University of Oklahoma> _______________________________________________> Numpy-discussion mailing list> Numpy-discussion@scipy.org> http://projects.scipy.org/mailman/listinfo/numpy-discussion
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