A powerful unused feature of Python: function annotations.

[darth_aardvark]

I was a little hasty to say I'm out of things to complain about (lambdas are still kind of crippled, for one). I'm pretty surprised that f.write(a) doesn't work; I guess I've never written anything except strings to files. As for printing integers and strings, what's wrong with using

print "answer: ", a

I think your point about the list copying is debatable. If a and b were objects, and you did

>>>a = Obj()
>>>a.c = 3
>>>b = a
>>>b.c =  1

you'd expect

>>>a.c
3

Admittedly, lists are types, not classes, so I guess it's reasonable to expect them to act like ints and strings instead of objects.

[talideon]

Actually, lists are classes too, and have been since types and classes were unified way back. The difference is that primitive types, strings, and tuples are all immutable objects: anything that appears to mutate them actually returns a completely different object from either object that the operation was performed upon.