[R] Fractional component of a number

[edward.m at psu.ac.th]

Dear all,
I am happy to accept that

> is.integer(1)
[1] FALSE

But I'm having difficulty with this one:

> as.integer((2.53-2)*100)
[1] 52

especially since:

> as.integer((1.53-1)*100)
[1] 53

Although I know that this is a precision issue since

> x <- (2.53-2)*100
> x-53
[1] -2.131628e-14

And I can always use the round function to get what I want, but I just
wonder if something is wrong here.

> sessionInfo()
R version 2.13.1 (2011-07-08)
Platform: i386-pc-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=Thai_Thailand.874  LC_CTYPE=Thai_Thailand.874   
LC_MONETARY=Thai_Thailand.874
[4] LC_NUMERIC=C                  LC_TIME=Thai_Thailand.874

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

Thanks,
Edward


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