[Numpy-discussion] use of concatenate with subclass of ndarray

[Pierre GM]

On Thursday 29 March 2007 12:04:51 Bryce Hendrix wrote:
> I spoke too soon, this code fails with the example you gave:

mmh, I tried to use the class you linked to last time: the only modifications 
I gave are listed below

class UnitArray(numpy.ndarray):
    __array_priority__ = 10.0
    default_unit = "meters"

    def __array_finalize__(self, obj):
        self.units = getattr(obj,'units',UnitArray.default_unit)

then I used that for testing:
    meters = "meters"
    feet = "feet"
    unit_ary_1 = UnitArray(numpy.array((1,2,3)), units=meters)
    unit_ary_2 = UnitArray(numpy.array((1,2,3)), units=meters)
    
    unit_ary_3 = UnitArray(numpy.array((1,2,3)), units=feet)

    new_unit_ary = numpy.concatenate([unit_ary_1, unit_ary_2])
    print new_unit_ary.units

And it seems to work. Could you be a bit more specific ?