Ben> I'm learning Python by teaching myself, ... I'm working on the Ben> project Euler problems, but I find that they don't really help my Ben> programming skills; they are more math focused.
I've found quite the opposite to be the case. I've been programming in Python for quite awhile and I find Project Euler helps me explore both the math side of the problems (reminding me of all I've forgotten) but also forces me to exercise various Python programming techniques and data structures in ways I typically wouldn't in my day-to-day programming existence. Some of the problems while conceptually simple to solve are intractable computationally with naive algorithms. Here are four of the five (I think) basic ways to solve Problem 1 (find the sum of all numbers below 1000 which are multiples of 3 or 5). If you run it notice the wide range of runtimes. Which ones degrade badly as N increases? #!/usr/bin/env python import time N = 1000 t = time.time() print sum([(n % 3 == 0 or n % 5 == 0) and n or 0 for n in xrange(N)]), print "%.6f" % (time.time() - t) t = time.time() print (sum(xrange(3, N, 3)) + sum(xrange(5, N, 5)) - sum(xrange(15, N, 15))), print "%.6f" % (time.time() - t) t = time.time() print sum([n for n in xrange(N) if n % 3 == 0 or n % 5 == 0]), print "%.6f" % (time.time() - t) t = time.time() print reduce(lambda x,y: x+y, filter(lambda n: n%3==0 or n%5==0, xrange(N))), print "%.6f" % (time.time() - t) t = time.time() print sum(set(xrange(3, N, 3)) | set(xrange(5, N, 5))), print "%.6f" % (time.time() - t) -- Skip Montanaro - [EMAIL PROTECTED] - http://smontanaro.dyndns.org/ -- http://mail.python.org/mailman/listinfo/python-list