On 15 Apr 2009, at 11:17, Raymond Hettinger wrote:
[Adam Atlas]
I propose adding a "default" keyword argument to max() and min(), which provides a value to return in the event that an empty iterable is passed.
Could you write your proposal out in pure python so we can see how it interacts with the key-keyword argument and how it works when the number of positional arguments is not one.
Here's one option... I'm going to cheat a little here and just wrap the built-in min, but a quick/simple answer could be:
def min2(*vars, **kw): try: if 'key' in kw: return min(*vars, key=kw['key']) return min(*vars) except Exception: if 'default' in kw: return kw['default'] raise
Will min(default=0) still return a TypeError? Will min(1, 2, default=0) return 0 or 1? Will min([1,2], default=0) return 1? # different from min([0,1,2])
# Your examples min2() -> TypeError min2(default=0) -> 0 min2(1,2,default=0) -> 1 min2([1,2], default=0) -> 1
# Iterator that yields things that are not comparable min2([1, set()]) -> TypeError min2([1, set()], default=7 ) -> 7
# Iterator that raises an exception def foo(): yield 1 raise ValueError
min(foo()) -> ValueError min2(foo()) -> ValueError min2(foo(), default=None) -> None
Jared