On Sun, 22 Jan 2006 18:29:45 +0100, Christoph Zwerschke wrote: > Alex Martelli wrote: >> Kay Schluehr <[EMAIL PROTECTED]> wrote: >>> range(3)**2 >>> But why isn't this interpreted as [0, 1, 4] like it is in Mathematica? >> >> Since range(3)*2 is [0, 1, 2, 0, 1, 2], it would be horribly, painfully >> inconsistent if **2 was interpreted as "square each item". > > Yes. Python does not interpreate the product of a list with a number as > a scalar product. Otherwise range(3)*2 should be [0, 1, 4] as well. > > For doing such things I would use a vector subtype of list.
Not everything needs to be a separate class! Why create a magic class for every piece of functionality you want? Just create functions that operate on existing classes! Instead of a class that supports cartesian products, make a function that takes two sequences and returns the cartesian product of them. (This will likely be best implemented as a generator.) If you write it properly, which is to say if you don't go out of your way to break it, this function will *automatically* work on any sequence type, lists, tuples, strings, and things you and I haven't even thought of. What advantage is there to creating a "list with cartesian product" subclass of list? -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
