On Mon, Oct 20, 2008 at 2:06 PM, pong <[EMAIL PROTECTED]> wrote: > > Thanks Marshall. I have thought about that as well. > Since I want to optimize time. I want to see if your method is faster > then a for loop. However, I run into something puzzling: > > vector( [k for k in range(10)]) results in an error. Sage compliant > about > > TypeError: unable to find a common ring for all elements
I get sage: vector( [k for k in range(10)]) (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) Are you sure that's what you typed? > > But if you check each element of the list, I got <type 'int'> > > So why SAGE is complaining? > > On Oct 19, 7:27 am, Marshall Hampton <[EMAIL PROTECTED]> wrote: >> Another option is to convert your list to a vector, and then convert >> it back. This is more awkward for a single operation but if you are >> doing lots of vector addition and scalar multiplication it can be the >> way to go. >> I.e. you can do: >> >> sage: a = [3,4] >> sage: a = list(2*vector(a)) >> sage: a >> [6, 8] >> >> -M. Hampton >> >> On Oct 19, 1:15 am, Robert Bradshaw <[EMAIL PROTECTED]> >> wrote: >> >> > On Oct 18, 2008, at 10:14 PM, Alex Ghitza wrote: >> >> > > Hmmm. As far as I know you can use _ as a placeholder for a >> > > variable, and it's meant for this kind of use (where you don't >> > > really want to introduce a new variable name). It's strange that >> > > it doesn't work for you. Can you post the error message that you get? >> >> > Actually, _ is an actual variable, though personally I find it a bit >> > harder to read than a normal letter. The one special thing about it >> > (in ipython at least) is that it constantly gets reassigned to the >> > last returned value, e.g. >> >> > sage: 1+2 >> > 3 >> > sage: _ >> > 3 >> >> > - Robert > > > -- William Stein Associate Professor of Mathematics University of Washington http://wstein.org --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
