Chris Barker writes: > But I still think the original: > > [g(y) for x in range(5) for y in [f(x)]] > > Is always going to be confusing to read.
But the point I was making with "def f(x=[0]):" was this: you have a situation where your desired semantics is "value of some type"[1], but the language's syntax doesn't permit a value of that type there, while "singleton sequence of that type" works fine. In fact, "singleton as value" is baked into Python in the form of str.__getitem__ and bytes.__getitem__. So we now have four use cases for singleton as value: two stringish actual types, and the two idioms "mutable default argument" and "local variable in comprehension". The horse is long since out of the barn. Steve Footnotes: [1] Both "value" and "type" are used rather loosely here. _______________________________________________ Python-Dev mailing list [email protected] https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com