On Wed, 23 Feb 2005 19:04:47 -0600, Andy Leszczynski wrote: > It is on Windows, Linux, Python 2.3: > > [GCC 3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk)] on linux2 Type "help", > "copyright", "credits" or "license" for more information. > >>> a=1.1 > >>> a > 1.1000000000000001 > >>> > >>> > >>> > Is it normal?
Yes. Quite normal. Floating point numbers are by nature approximations. When you enter your variable "a" at the prompt, you are asking for a very raw (i.e totally unformatted!) dump of what your variable "a" contains. It is the most precise representation of the float 1.1 that your computer can store. It is probably the best precision your hardware math processor subsystem has to offer. And, incidentally, that ain't too shabby since a 1 in the 16th decimal place ain't worth spit! Try putting a print statement in front of your variable. >>> print a >>> 1.1 The print statement ,by itself, adds the most minimial formatting, which amounts to dropping the last significant digit your math processor holds. That last digit will *always* contain some arithmetic slop. If you do any serious work with floats, you will want to learn about significant figures and the use of the very essential round() function in whatever language you are using. If you do, you will find that this situation is really a math thing and has little to do with computers or any particular language. It's the exact same problem one runs into when using a slide rule. If anyone remembers those things :-) Thomas Bartkus -- http://mail.python.org/mailman/listinfo/python-list
