On Tue, 15 Mar 2016 07:31 am, BartC wrote: > But how do you pass something that refers to a itself?
You can't. "Names" are not first-class values in Python. You can pass a string which represents a name, and a namespace, but you cannot pass just an unquoted name and have Python automatically resolve it as a writable reference to a name in a namespace. I'm only aware of a handful of languages which support this sort of reference semantics: Pascal (of course!), Algol uses the similar "pass by name" semantics using thunks, C++, and Visual Basic. > There are good reasons for wanting to do so. Try writing this function > in Python: > > def swap(a,b): > b,a = a,b You can't. But you don't need to. The idiomatic way to swap two values in Python is: a, b = b, a This works for any number of values: a, b, c, d = d, c, a, b and it even works (with care) for references other than bare names: a[0], a[1] = a[1], a[0] -- Steven -- https://mail.python.org/mailman/listinfo/python-list
