A recarray of arrays

Travis Oliphant oliphant.travis at ieee.org
Sat Oct 28 19:08:53 CDT 2006


Pierre GM wrote:
> Folks,
> What is the easiest way to define a recarray of arrays ?
> For example, I'd need something like that:
> Given three arrays
>   
>>>> x = N.arange(5)
>>>> y = x+1
>>>> z = N.sqrt(x)
>>>>         
> and a list of names:
>   
>>>> n = ['x','y','z']
>>>>         
> Define a 3-record array with two fields: the first one being a ndarray (in x, 
> y or), the second a string (in n).
>
> I'm a bit at loss with the definition of the corresponding dtype...
>   

I'm a little unclear one what you want.

Here is a data-type whose first field is a name and whose second field 
is a 5-element array:

dt = N.dtype([('name', 'S10'), ('data', float, (5,))])

Then:

a = array([('x',x),('y',y),('z',z)],dt)

gives

array([('x', [0.0, 1.0, 2.0, 3.0, 4.0]), ('y', [1.0, 2.0, 3.0, 4.0, 5.0]),
       ('z', [0.0, 1.0, 1.4142135623730951, 1.7320508075688772, 2.0])],
      dtype=[('name', '|S10'), ('data', '<f8', (5,))])


-Travis







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