On Jun 9, 6:05 pm, "Gabriel Genellina" <gagsl-...@yahoo.com.ar> wrote: > En Tue, 09 Jun 2009 18:33:39 -0300, Esmail <ebo...@hotmail.com> escribió: > > > random.random() will generate a random value in the range [0, 1). > > > Is there an easy way to generate random values in the range [0, 1]? > > I.e., including 1? > > I think you shouldn't worry about that - the difference may be as small as > 2**-53, or 0.0000000000000001 > > > I am implementing an algorithm and want to stay as true to the > > original design specifications as possible though I suppose the > > difference between the two max values might be minimal. > > > ps: I'm confused by the docs for uniform(): > > > random.uniform(a, b) > > Return a random floating point number N such that a <= N <= b for a > > <= b > > > this seems to imply an inclusive range, ie. [a,b] > > random() guarantees a semi-open interval (could return 0, but never 1). > But once you start to operate with the numbers, the limits become fuzzy. > > a<b & n>0 => n.a<n.b > > The above holds for real numbers but not always for floating point > arithmetic, so one cannot guarantee the semi-open interval anymore: > > py> a=10.0 > py> b=11.0 > py> z = 0.9999999999999999 # assume random.random returned this > py> z<1 > True
That means the interval is still [0,1). To put it another way: >>> z=0.9999999999999999 >>> z==1 False > py> a+(b-a)*z < b # the expression used for uniform(a,b) > False > py> a+(b-a)*z > 11.0 What you do with the number after it's created is not random's concern. > > The docs are already updated to reflect > this:http://svn.python.org/view/python/trunk/Doc/library/random.rst?r1=687... The docs are now wrong. Why would they do that? > > -- > Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
