convert a list of Quantity object into an array of Quantity object

[xiki-tempula]

I wonder if it is possible to have a function to convert a list of Quantity into an array of Quantity object?

>>> import numpy as np
>>> import quantities as pq
>>> a = 1 * pq.e
>>> a
array(1.) * e
>>> b = [a, a]
>>> b
[array(1.) * e, array(1.) * e]
>>> np.array(b)
array([1., 1.])

So I wonder if there could be a function

>>> pq.array(b)
array([1., 1.]) * e

[twmr]

I'm using the following function for this use-case (the name of it could be improved, though)

def quantitylistrescale(seq, unit=None):
    """Convert list of quantities to a rescaled quantity array

    Examples
    --------

    >>> import quantities as pq
    >>> a = 3 * pq.m; b = 2.5 * pq.mm
    >>> quantitylistrescale([a, b], 'cm')
    array([3.0e+02, 2.5e-01]) * cm

    If no ``unit`` is given, the elements will be rescaled to the unit of the
    first quantity.

    >>> quantitylistrescale([a, b])
    array([3.0e+00, 2.5e-03]) * m

    >>> quantitylistrescale([])
    Traceback (most recent call last):
        ...
    StopIteration
    >>> quantitylistrescale([3 * pq.m, 4 * pq.V])
    Traceback (most recent call last):
        ...
    ValueError: Unable to convert between units of "V" and "m"

    """
    assert all(isinstance(item, pq.Quantity) for item in seq), (
        f"{seq} contains objects which are not of type pq.Quantity")

    if unit is None:
        first = next(iter(seq))
        unit = first.dimensionality.string

    rescaled_seq = [item.rescale(unit).magnitude for item in seq]

    return pq.Quantity(rescaled_seq, unit)

[xiki-tempula]

I'm using a similar function (without type checking as I know what is in the array) but I felt that it might be good to have it in the package, like pq.array().