[Numpy-discussion] dumb structured arrays question

David Warde-Farley dwf@cs.toronto....
Thu Sep 17 17:12:01 CDT 2009

If I have a 1-dimensional array with a structured dtype, say str,  
float, float, float, float.... where all the float columns have their  
own names, and I just want to extract all the floats in the order they  
appear into a 2D matrix that disregards the dtype metadata... Is there  
an easy way to do that?

Currently the only thing I can think of is

out = []
for name in arr.dtype.names:
	if name != 'condition': # my single str field
out = np.array(out)

Is there already some convenience function for this, to coerce numeric  
compound dtypes into an extra dimension?

It seems conceivable that I might be able to pull some dirty trick  
with stride_tricks that would even allow me to avoid the copy, since  
it'd just be a matter of an extra few bytes on the 2nd dimension  
stride to skip over the string data.



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