On Thu, Aug 30, 2007 at 10:40:01AM +0300, dmitrey wrote: > what's the easiest way to create bool array that contains m1 True, m2 > False, m3 True, m4 False? Don't know whether there is any absolute easiest way, but this should work: In [6]: x = N.ones(30).astype(bool) In [7]: x[1::2] = False Cheers Stéfan