Terry Reedy wrote:
Alexander Belopolsky wrote:
Terry Reedy wrote:
I had exactly the same idea, but did not post because it violates the general rule that mutators return None.
Is there such a rule? What about set/dict pop?
The rule perhaps should be restated as 'Collection mutators return None or possible an item but not the collection.'
And to clarify the rationale for that guideline: it is to make it clear that the mutator is changing the container in place and *not* creating a new container object. myset.pop() # No new container, returns popped object mylist.sort() # No new container, returns None sorted(mylist) # New container, so return it mystr.lower() # Creates new string, so return it Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia ---------------------------------------------------------------