[Numpy-discussion] String manipulation

Christopher Barker Chris.Barker@noaa....
Wed Jul 22 13:33:56 CDT 2009


Stéfan van der Walt wrote:
> You cannot use view on an array scalar, so you'll have to convert to
> an array first:
> 
> x = x.reshape((1,))
> x.view('S1')

Bingo!

Thanks, Stéfan.

I don't know why one can't uwe view on a scalar -- there is still a dat 
pointer isn't there?, and it can be reshaped. Butno matter, now I have a 
  one liner that splits a string up into fixed fields, and returns a 
float array of the numbers in those fields:

np.array((line,)).view(dtype='S%i'%field_len).astype(np.float)

I suspect this is faster than the list comp method, though I haven't 
tested it -- I"ll leave that to someone that actually has this problem 
to solve ;-)

I've enclosed a bit of test code with a few other approaches as well.

-Chris




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