Issue 798046: select module doesn't allow any iterable. (original) (raw)

This issue has been migrated to GitHub: https://github.com/python/cpython/issues/39154

classification

process

Created on 2003-08-31 07:31 by jemfinch, last changed 2022-04-10 16:10 by admin. This issue is now closed.

Messages (4)
msg53990 - (view)	Author: Jeremy Fincher (jemfinch)	Date: 2003-08-31 07:31
The select module only allows lists, not any iterable. While this may slightly increase efficiency for the select.select() function itself, for many applications passing select.select a sets.Set would probably be much more efficient (i.e., when things are being added/removed from the readable or writable lists quite often, the O(n) removal of lists would certainly be worse than the O(1) removal of sets.)
msg53991 - (view)	Author: Armin Rigo (arigo) *	Date: 2003-09-02 18:23
Logged In: YES user_id=4771 Using select.poll() instead of select.select() might be a good alternative, at least on platforms that support it, if the sets are getting large enough for you to want to avoid having to build lists explicitely as in : select.select(list(a), list(b), list(c))
msg53992 - (view)	Author: Brett Cannon (brett.cannon) *	Date: 2003-09-06 22:22
Logged In: YES user_id=357491 There seems to be two things that are preventing the use of an object that supports the iterator protocol instead of a list. One is the explicit check that the arguments are lists; PyList_Check is run on the passed-in lists for a basic sanity check. Then there is a call to a function called list2set that takes in a Python list and then sets the passed-in fd_set properly. In that function there is nothing that screams "we should only use lists" beyond it allows assuming a list and thus doesn't have any hoops to jump through. But the iterator protocol was set up to minimize hoop jumping. There seems to be little stopping a move over to using the iterator protocol beyond a minimial amount of recoding to rip out the list check to replace it with PyIter_Check and instead of using a 'for' loop through a list you just use a 'while' calling PyIter_Next . But since this seems to have gone so long without being changed I would feel better about having someone tell me it is okay to change. I will email python-dev and ask.
msg53993 - (view)	Author: Brett Cannon (brett.cannon) *	Date: 2003-09-10 19:39
Logged In: YES user_id=357491 Rev. 2.74 of Modules/selectmodule.c has select.select() accept a sequence (as defined by PySequence_Fast()) for its first three arguments; this includes sets. Changed to an RFE since it wasn't really a bug and closed.