"Gary Wessle" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Erik Max Francis <[EMAIL PROTECTED]> writes: > > > chun ping wang wrote: > > > > > Hey i have a stupid question. > > > How do i get python to print the result in only three decimal > > > place... > > > Example>>> round (2.995423333545555, 3) > > > 2.9950000000000001 > > > but i want to get rid of all trailing 0's..how would i do that? > > > > Floating point arithmetic is inherently imprecise. This is not a > > Python problem. > > does python support true rations, which means that 1/3 is a true > one-third and not 0.333333333 rounded off at some arbitrary precision?
At risk of being boring ;-) - Python supports both rational and irrational numbers as floating point numbers the way any language on any digital computer does - imprecisely. A "true" (1/3) can only be expressed as a fraction. As soon as you express it as a floating point - you are in a bit of trouble because that's impossible. You can not express (1/3) as a floating point in Python any more than you can do it with pencil and paper. You can be precise and write "1/3" or you can surrender to arithmetic convenience and settle for the imprecise by writing "0.333333333", chopping it off at some arbitrary precision. Which is exactly what you did in your post ;-) Thomas Bartkus -- http://mail.python.org/mailman/listinfo/python-list
