On Wed, Apr 10, 2013 at 5:16 PM, Max Bucknell <mpwb...@york.ac.uk> wrote: > I also have a function to generate the dot product of these two vectors. In > Java, such a function would be put as a method on the class and I would do > something like: > > >>> a.dot_product(b) > 7 > > and that would be the end of it. But in Python, I can also have: > > >>> dot_product(a, b) > 7 > > Which of these two are preferred in Python? And are there any general > guidelines for choosing between the two styles, or is it largely a matter of > personal preference?
The advantage to the latter is that it potentially allows you to implement dot products for other types using the same function. Using the method, a must be a Vector instance, but using the function it remains unrestricted. This is useful because functions are first-class objects in Python. Suppose that you find yourself wanting to pass that dot_product operation to some other function, e.g. map(). Using the function version you just pass in dot_product -- map(dot_product, seq1, seq2) -- and the mapped sequences can then contain any types that dot_product has been implemented to handle. Using the method version, you would have to pass in the unbound Vector.dot_product method -- map(Vector.dot_product, seq1, seq2), and then the method will only accept Vector instances in seq1. -- http://mail.python.org/mailman/listinfo/python-list
