I agree with Nils. I just started using forall and exists and found it stupid to have to append [0] to get the boolean value. And given their existence I never looked further to find the python any() and all() functions.
On 30/01/2008, Nils Bruin <[EMAIL PROTECTED]> wrote: > > On Jan 30, 2:49 pm, "Mike Hansen" <[EMAIL PROTECTED]> wrote: > [...] > > name. Also, there are functions in Python which have similar > > functionality. > > > > sage: l = [1,2,3] > > sage: any([i == 2 for i in l]) > > True > > sage: all([i == 2 for i in l]) > > False > > That's instructive. In that case, forall and exists should probably > have their help extended by a pointer that if a witness is not > required, the user should type: > > any(P(s) for s in S) > > or > > all(P(s) for s in S) > > That's actually a nicer syntax anyway and it would be a shame if > people keep hobbling along with forall and exists when there is a much > nicer option. (I got a tab completion hit on "forall" and "exists" and > assumed those were the right functions to use. They are often not). > That teaches me to *not* write patches :-) On the contrary! But change it to a patch for the docstrong for exists() and forall(). John > > > On Jan 30, 2008 2:45 PM, Nils Bruin <[EMAIL PROTECTED]> wrote: > > > > > > > > > Presently, because forall and exists return tuples rather than > > > booleans, their return value is always True, so they cannot be used as > > > a predicate, which is very unintuitive given their names. Proposed > > > solution: optional parameter witness (default: False) that determines > > > return value type. > > > > > Ticket (has patch) > > > > >http://trac.sagemath.org/sage_trac/attachment/ticket/1987 > > > -- John Cremona --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
