[Numpy-discussion] rank-0 arrays

Pearu Peterson pearu at cens.ioc.ee
Mon Sep 16 16:10:04 CDT 2002


On Mon, 16 Sep 2002, Travis Oliphant wrote:

> > Frankly, I have no idea what the implimentation details would be, but
> > could we get rid of rank-0 arrays altogether? I have always simply found
> > them strange and confusing... What are they really neccesary for
> > (besides holding scalar values of different precision that standard
> > Pyton scalars)?
> 
> With new coercion rules this becomes a possibility.  Arguments against it
> are that special rank-0 arrays behave as more consistent numbers with the
> rest of Numeric than Python scalars.  In other words they have a length
> and a shape and one can right N-dimensional code that works the same even
> when the result is a scalar.

In addition, rank-0 arrays are mutable while Python scalars are not.
Mutability is sometimes useful (e.g. when emulating C or Fortran
calls in Python) but often also evil due to its unpythonic side effect.

Pearu





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