Difference

Dear List,
can anyone explain me this result (Windows XP, R 2.0.1):

 > (0.2-0.1)==0.1

[1] TRUE

 > (0.3-0.2)==0.1

[1] FALSE

Yes. Floating point arithmetic isn't as accurate as you think. Your
numbers have a simple representation in decimal format, but are stored
in the computer in binary, so there is some rounding error.

(0.3-0.2) - 0.1

[1] -2.775558e-17

You probably want to use "all.equal" to test for "near" equality

all.equal(0.3-0.2,0.1)

[1] TRUE

identical(all.equal(0.3-0.2,0.1), TRUE)

[1] TRUE

See the help pages for all.equal and identical for more details.

Martyn