Potential Bug with Numbers

[jhpnovice]

version
_
platform x86_64-w64-mingw32
arch x86_64
os mingw32
system x86_64, mingw32
status
major 3
minor 6.1
year 2019
month 07
day 05
svn rev 76782
language R
version.string R version 3.6.1 (2019-07-05)
nickname Action of the Toes

Hi,
There's some weird numeric issue with the version above that I'm using.
I get FALSE for 0.06 + 0.01 == 0.07 but TRUE for 0.02 + 0.05 == 0.07.
Also, I get FALSE for 0.7 %in% seq(0.1, 1, 0.1). And I get the following:

c(0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1) == seq(0.1, 1, 0.1)
[1] TRUE TRUE FALSE TRUE TRUE TRUE FALSE TRUE TRUE TRUE

Only third and seventh give FALSE. Same with %in%:

c(0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1) %in% seq(0.1, 1, 0.1)
[1] TRUE TRUE FALSE TRUE TRUE TRUE FALSE TRUE TRUE TRUE

I am not the only one having this; my coworker sees the same issue with his rstudio.
Can someone please tell me what I'm missing here? Or is this a bug?

[lars]

Comparing floating numbers can be tricky when one is not aware of the following:

The only numbers that can be represented exactly in R’s numeric type are integers and fractions whose denominator is a power of 2. All other numbers are internally rounded to (typically) 53 binary digits accuracy. As a result, two floating point numbers will not reliably be equal unless they have been computed by the same algorithm, and not always even then [..] The function all.equal() compares two objects using a numeric tolerance of .Machine$double.eps ^ 0.5 . If you want much greater accuracy than this you will need to consider error propagation carefully.

R FAQ

So,

0.06 + 0.01 == 0.07
#> [1] FALSE
all.equal(0.06 + 0.01, 0.07)
#> [1] TRUE

^{Created on 2021-02-16 by the reprex package (v1.0.0)}

[jhpnovice]

Thank you. That makes it clear. I did think the issue is too shallow to remain as an unfixed bug till today.
Then I guess the solution is to use some other condition in if statement.