Hi, How to truncate float number after dot? I suppose it would be easy. Thank in advance MT

on 2007-07-26 11:06

on 2007-07-26 11:14

On 7/26/07, Marcin Tyman <m.tyman@interia.pl> wrote: > Hi, > > How to truncate float number after dot? I suppose it would be easy. > > Thank in advance 19.84.round #=> big brother is watching you

on 2007-07-26 11:15

On 7/26/07, Marcin Tyman <m.tyman@interia.pl> wrote: > Hi, > > How to truncate float number after dot? I suppose it would be easy. > > Thank in advance > MT > -- > Posted via http://www.ruby-forum.com/. > > irb(main):001:0> 12.68.floor => 12 irb(main):002:0> 12.68.ceil => 13 Pat

on 2007-07-26 11:16

On 7/26/07, Pat Maddox <pergesu@gmail.com> wrote: > > > > > irb(main):001:0> 12.68.floor > => 12 > irb(main):002:0> 12.68.ceil > => 13 > > Pat > Gah, I forgot the all important round! irb(main):003:0> 12.68.round => 13 irb(main):004:0> 12.38.round => 12 Pat

on 2007-07-26 11:29

2007/7/26, Pat Maddox <pergesu@gmail.com>: > > irb(main):001:0> 12.68.floor > => 13 > irb(main):004:0> 12.38.round > => 12 12.38.to_i robert

on 2007-07-26 12:52

I didn't mean to truncate all. But i.e. to round to several places after dot.

on 2007-07-26 13:05

2007/7/26, Marcin Tyman <m.tyman@interia.pl>: > I didn't mean to truncate all. But i.e. to round to several places after > dot. Usually it's better to calculate with full precision and round when printing, e.g. using printf of irb(main):022:0> "%4.1f" % 1.0 => " 1.0" irb(main):023:0> "%4.1f" % 1.04 => " 1.0" irb(main):024:0> "%4.1f" % 1.05 => " 1.1" Kind regards robert

on 2007-07-26 16:20

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Marcin Tyman wrote: > How to truncate float number after dot? I suppose it would be easy. Rounding to a certain number of digits works as follows: Let n be the number of digits following the decimal point you want to obtain. Then 1. Multiply the number by 10 to the power n (i.e. by 10.0 ** n) 2. Round the number (i.e. use Float#round) 3. Divide the result by 10 to the power n The latter can either be done by division by 10.0 ** n or by multiplication by 0.1 ** n. But as Robert Klemme already noted: It rarely makes sense to actually round numbers. It usually makes more sense to compute with the available precision and limit the output to the wanted number of digits. Anyway, sometimes it makes sense. For example if you are required by law to round intermediate calculation results to a certain amount of digits. But in such cases one should not at all use floating point numbers for the computations. One would rather use integers, fixed-point arithmetics (as e.g. supported by COBOL) or the Decimal data type from Microsoft's Common Type System (e.g. supported by C#). Josef 'Jupp' Schugt - -- Blog available at http://www.mynetcologne.de/~nc-schugtjo/blog/ PGP key with id 6CC6574F available at http://wwwkeys.de.pgp.net/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFGqK1/rhv7B2zGV08RArEPAJ0Z6ihtrVLvBn0ODryW8Ptu3uqplACfTuT1 muYIWqBXnWKO4ZwEKYMiVik= =5H5E -----END PGP SIGNATURE-----