Equivalents of Ruby's "!" methods?

[mumbler at gmail.com]

On Aug 26, 9:47 am, Steven D'Aprano <st... at REMOVE-THIS-
cybersource.com.au> wrote:
> On Mon, 25 Aug 2008 17:04:07 +0000, Grzegorz Staniak wrote:
> > On 25.08.2008, Terry Reedy <tjre... at udel.edu> wroted:
>
> >> The newish sorted() and reversed() built-ins were meant to complement
> >> list.sort and list.reverse, not replace them.
>
> > BTW, is there a reason why sorted() on a list returns a list, while
> > reversed() on the same list returns an iterator?
>
> Until the day that somebody discovers how to sort a list without seeing
> all the items first, there's no point in sorted() returning an iterator.

To nitpick, this is not strictly true: sure, you're at best O(nlogn)
on sorting the entire list, but you could return the first element of
the 'sorted' list in O(n) (if you don't mind using a O(n^2) algorithm
for the whole sort). i.e. if you have a use case where you're only
likely to look at the first few elements of a sorted list, it would
make some sense to have an iterator.