Calculating Body Mass Index

The Body Mass Index is a good tool to estimate the body fat for a person from their height and weight. It is quite easy to calculate:

   bmi = weight / height ** 2

Things are getting a bit more complicated if I want to get the BMI for a bunch of people. I'd like to write something like this:

   bmis = weights / heights ** 2

Problem is that I can't do that with standard python lists, since there is no overload for mathematic operators working on them. I should write a piece of code that works on single components and puts the result in another list.

Luckly I could use the numpy library, designed expressly to provide better numeric capability to python. It is just a matter of using the array class. Here is an example:

   import numpy

   heights = numpy.array([1.78, 1.52, 1.63, 1.68])
   weights = numpy.array([65, 82, 63, 65])
   bmis = weights / heights ** 2

   print(bmis)