Zack Weinberg wrote: > I have noticed that in R 2.5.0, no method of textual output will print > a "double" mode quantity with more than 15 digits after the decimal > point. From the help page (?print.default) it appears that this is > intentional, since digits after the fifteenth may be uncertain. > However, fifteen digits after the decimal point are not enough to > represent all the values that an IEEE-double can take. (You need one > more.) This means it is now impossible to write out data in textual > format (e.g. in order to manipulate it with another program) and read > back in exactly the same values. Some analyses are sensitive to this > sort of extra rounding, especially if it happens repeatedly. > > I'd really appreciate some way of forcing R to print enough digits to > represent every possible IEEE double value. I would also argue that > this should be the default behavior of dump(), write.table() and > friends, and save(...,ascii=TRUE), to prevent data loss.
Example: formatC(exp(1), digits=100, width=-1) Uwe Ligges > [Tangentially, support for C99 hexadecimal notation for floating point > values in input and output would also be nice, but wouldn't help much > for interoperability, since very few programs understand it.] > > zw > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
