R: why the == operator cannot find a value in a numeric vector

Asked Aug 15 '17 at 01:25

Active Aug 15 '17 at 01:25

Viewed 37 times

I just don get why the following situation can happen.

X$angle.corrected is a numeric vector and the value 2399.81 is in it. Why can't the == operator find it?

> X$angle.corrected[688]
[1] 2399.81
> sum(X$angle.corrected==2399.81)
[1] 0
> class(X$angle.corrected)
[1] "numeric"

asked Aug 15 '17 at 01:25

John

Floating point arithmetic is not exact in R (and many other languages). – Tim Biegeleisen Aug 15 '17 at 01:28
as noted in the linked answer, examine `sprintf("%.54f", X$angle.corrected[688])`. Use `all.equal` or define your own equality tolerance. – MichaelChirico Aug 15 '17 at 01:29

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