numeric equality

Dear all,

 

I am totally confused by the following R output, but don't have a clue
for it.

 

a <- 1 - 0.2

a == 0.8

[1] TRUE

a <- 1 - 0.8

a == 0.2

[1] FALSE

Hi Yu,

First of all read FAQ 7.31 (Why doesn't R think these numbers are
equal?)

Second, in this case, use all.equal

a <- 1 - 0.8

a == 0.2
[1] FALSE

all.equal(a,0.2)
[1] TRUE

Bernardo Rangel Tura, M.D,MPH,Ph.D
National Institute of Cardiology
Brazil