Simon Burton wrote:

Is there a reason why dtype's are unhashable ? (ouch)

No one thought about it, probably. If you would like to submit a patch, I think it we would check it in.

On another point, is there a canonical list of dtype's ? I'd like to test the dtype of an array, and I always end up with something like this:

if array.dtype == numpy.dtype('l'): ...

When I would prefer to write something like:

if array.dtype == numpy.Int32: ...

numpy.int32 There is a list on page 20 of _The Guide to NumPy_. It is included in the sample chapters: http://www.tramy.us/scipybooksample.pdf

(i can never remember these char codes !)

Alternatively, should dtype's __cmp__ promote the other arg to a dtype before the compare ? I guess not, since that would break a lot of code: eg. dtype(None) is legal.

Correct, it should not. -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco

Simon Burton wrote:

On Sun, 28 May 2006 14:33:37 -0500 Robert Kern wrote:

...

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if array.dtype == numpy.Int32: ...

numpy.int32

No that doesn't work.

...

...

...

numpy.int32

...

...

...

numpy.int32 == numpy.dtype('l')

False

...

...

from numpy import * a = linspace(0, 10, 11) a.dtype == dtype(float64) True

-- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco

On Sun, 28 May 2006 14:36:47 -0600 Travis Oliphant wrote:

Simon Burton wrote:

...

On Sun, 28 May 2006 14:33:37 -0500 Robert Kern wrote:

...

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if array.dtype == numpy.Int32: ...

numpy.int32

No that doesn't work.

Yeah, the "canonical" types (e.g. int32, float64, etc) are actually scalar objects. The type objects themselves are dtype(int32). I don't think they are currently listed anywhere in Python (except there is one for every canonical scalar object). ...

Can we promote the numarray names: Int32 etc. to their dtype equivalents ? I don't see why having Int32='l' is any more usefull that Int32=dtype('l'), and the later works with cmp (and also is more helpful in the interactive interpreter). Simon. -- Simon Burton, B.Sc. Licensed PO Box 8066 ANU Canberra 2601 Australia Ph. 61 02 6249 6940 http://arrowtheory.com