How does R work with bigints?

Question

I have an 18 digit int which R doesn't understand, it returns a different value from what I enter

options(digits = 22)
> as.numeric(123456789123456789)
[1] 123456789123456784

Also when using bit64 which has an integer64 class

> as.integer64(123456789123456789)
integer64
[1] 123456789123456784

Are there other packages that can interpret this number correctly?

score 5 · Answer 1 · edited May 23 '17 at 12:32

5

Use as.integer64("123456789123456789"). 123456789123456789 is a double (to avoid integer overflow) and thus subject to floating point imprecision. as.integer64(123456789123456789) creates an integer64 from this double.

edited May 23 '17 at 12:32

Community

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answered Oct 09 '15 at 16:53

Roland

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score 2 · Answer 2 · answered Oct 09 '15 at 17:07

Here's an answer that is similar to the one suggested by @Roland; just using another library.

library(gmp)
x <- as.bigz("123456789123456789")
#> x
#Big Integer ('bigz') :
#[1] 123456789123456789

In this case, too, the number needs to be put in quotation marks to prevent floating-point rounding errors.

How does R work with bigints?

2 Answers2