[Rd] Arithmetic bug? (found when use POSIXct) (PR#10776)

bozhou1981 at hotmail.com bozhou1981 at hotmail.com
Sun Feb 17 21:50:13 CET 2008


Hi Gabo,

FAQ 7.31 does not apply to this. "numeric" in R is 64bit which is large eno=
ugh to handle this.

I
figured out the cause is that Sys.time() gives millisecond value while
b<-as.POSIXct(format(a,tz=3D"GMT")) cuts off that part.=20

Then of course a-b is not 5 hours!

Do it again with "options(digits=3D22)" and you will see what actually happ=
ened there.

The recommended code from R News is not aware the truth that POSIXlt can re=
present sub-second time.

Cheers,

B
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