[Numpy-discussion] Suppressing "nesting" (recursion, descent) in array construction.

Francesc Altet faltet@carabos....
Thu Jun 21 10:07:16 CDT 2007


El dj 21 de 06 del 2007 a les 06:24 -0700, en/na Michael McNeil Forbes
va escriure:
> >> key_array = empty(len(keys),dtype=tuple)
> >> key_array[:] = keys[:]
> >
> > the later two statements can also be written as:
> >
> > key_array = array(keys, dtype=tuple)
> 
> These are not equivalent:
> 
>  >>> keys = [('a',1),('b',2)]
>  >>> key_array = array(keys, dtype=tuple)
>  >>> key_array
> array([[a, 1],
>         [b, 2]], dtype=object)
> 
>  >>> key_array = empty(len(keys),dtype=tuple)
>  >>> key_array[:] = keys[:]
>  >>> key_array
> array([('a', 1), ('b', 2)], dtype=object)

Ops. You are right.  I think I was fooled by the 'dtype=tuple' argument
which is in fact equivalent to 'dtype=object'.

-- 
Francesc Altet    |  Be careful about using the following code --
Carabos Coop. V.  |  I've only proven that it works, 
www.carabos.com   |  I haven't tested it. -- Donald Knuth



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