Page - 116 - in Programming for Computations – Python - A Gentle Introduction to Numerical Simulations with Python 3.6, Volume Second Edition

116 5 SomeMorePythonEssentials ball_function.py, while the other two, time_of_flight and max_height, compute the time of flight and maximumheight attained, respectively (consult any introductorybookonmechanics regardingthe implementedformulas). Inlinewithgoodprogrammingpractice,wealsoequipourmodulefilewithadoc string on top. Generally, that doc string should give the purpose of the module and explainhowthemoduleisused.Morecomprehensivedocstringsareoftenrequired for largerandmore“complicated”modules (here,ourdocstring isverysimple,but professionalprogrammerswrite theirdocstringswithgreatcare10).Themodulefile reads: """ Module for computing vertical motion characteristics for a projectile. """ def y(v0, t): """ Compute vertical position at time t, given the initial vertical velocity v0. Assume negligible air resistance. """ g = 9.81 return v0*t - 0.5*g*t**2 def time_of_flight(v0): """ Compute time in the air, given the initial vertical velocity v0. Assume negligible air resistance. """ g = 9.81 return 2*v0/g def max_height(v0): """ Compute maximum height reached, given the initial vertical velocity v0. Assume negligible air resistance. """ g = 9.81 return v0**2/(2*g) # Other function definitions could be added here... As with built-in modules, the built-in help function can be used to retrieve documentationfromuser-definedmodules: In [1]: import vertical_motion In [2]: help(vertical_motion) Help on module vertical_motion: NAME vertical_motion FILE /.../.../.../vertical_motion.py 10 https://www.python.org/dev/peps/pep-0257/.