how do I make a numpy array from a list of pint quantities

Question

import numpy as np from pint import UnitRegistry unit = UnitRegistry() Q_ = unit.Quantity a = 1.0*unit.meter b = 2.0*unit.meter # some calculations that change a and b x=np.array([a.magnitude,b.magnitude])*Q_(1.0,a.units) will make a numpy array from variables a and b which are Pint quantities. It is somewhat crude as there is no guarantee that a and b have the same units. Is there a cleaner way to do it? Do I need to write a function? JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

You should convert to a base unit with to_base_units() before creating a numpy array from it, no need to write a function for this, a simple list comprehension will do it nicely. If you're doing numerically heavy calculations on x you probably will want to keep it in a reference unit and use it as a raw array (without attached unit), and limit the unit conversions to the input/output phase of the program. import numpy as np from pint import UnitRegistry unit = UnitRegistry() Q_ = unit.Quantity a = 1.0 * unit.meter b = 2.0 * unit.meter c = 39.37 * unit.inch # A list with values in different units (meters and inches) measures = [a, b, c] # We use a comprehension list to get the magnitudes in a base unit x = np.array([measure.to_base_units().magnitude for measure in measures]) print x * Q_(1.0, unit.meter) >> [ 1. 2. 0.999998] meter