On 2004-10-27 at 19:37+0900 Stijn De Saeger wrote:
hello
Thanks for the explanation, at first it seemed like enumFromThenTo would indeed give me the functionality I am looking for. But then all of GHCi started acting weird while playing around... this is a copy-paste transcript from the terminal.
*S3> 0.5 `elem` [0.0,0.1..1.0] True *S3> 0.8 `elem` [0.6,0.7..1.0] False *S3> 0.8 `elem` [0.6,0.7..1.0] False *S3> [0.6,0.7..0.9] [0.6,0.7,0.7999999999999999,0.8999999999999999] *S3>
????????
why would the floating point step size work the first time but not the second? confusing...
Doubles aren't real numbers, they're binary floating point. 1/5 doesn't have a finite binary representation. Also what gets printed out has been converted back to decimal and rounded a bit. So don't expect too much from them! You probably want to use Double -> Bool, and possibly look at infinite precision real arithmetic too. Jón -- Jón Fairbairn Jon.Fairbairn@cl.cam.ac.uk