2008/10/26 David Joyner <[EMAIL PROTECTED]>: > > I'm sure someone else can give a better answer, but hopefully > the below examples help a little. > > On Sun, Oct 26, 2008 at 7:56 AM, Rolandb <[EMAIL PROTECTED]> wrote: >> >> Hi, >> To learn SAGE takes a while, and good exercises are scarce. >> It was mentioned before, but the site http://projecteuler.net/ is >> interesting. The idea is to solve relatively simple mathematical >> problems and the level is going up slowly. For instance group >> operations, read/write to a file, speed are topics you will >> encounter. >> >> Until now I solved 38 problems. Two questions arise: >> 1. Suppose you have two functions: SLOW and FAST which return the >> boolean True or False. >> Is there a difference in speed between: >> a. If SLOW and FAST: …. >> b. If FAST and SLOW: …. >> The second option seems faster because only SLOW is executed if >> FAST==True. Or does the compiler checks this? > > > sage: a = 1; b = 2 > sage: if a == 1 and b == 2: print a > ....: > 1 > sage: if a == 0 and c == 2: print a > ....: > sage: > > If it evaluated both it would give a "c is undefined" error. > On the other hand, if you replace c by lambda then you will get > an error, so the second expression is not ignored entirely. > > >> >> 2. Is there a more elegant way for: >> for k1 in range(-2,3): >> for k2 in range(-2,3): >> for k3 in range(-2,3): >> for k4 in range(-2,3): >> for k5 in range(-2,3): >> for k6 in range(-2,3): >> for k7 in range(-2,3): ?
for k in cartesian_product_iterator([range(-2,3) for i in [1..7]]): Now k[0], ..., k[6] take on all 6-tuples from -2,...,-2 to +2,...,+2 John Cremona > > One idea is you could try > > L = range(-2,3) > M = Tuples(L,7) > for m in M: > k1 = m[0]; ...; k7 = m[6] > ... > > There might be faster ways though. > >> >> Roland >> >> > >> > > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
