How do I convert 64-bit hexadecimal strings in R?

Question

> library(int64)
> as.int64("7f2d36a2a000")
[1] NA
Warning message:
In as.int64("7f2d36a2a000") : NAs introduced
> as.int64("0x7f2d36a2a000")
[1] NA
Warning message:
In as.int64("0x7f2d36a2a000") : NAs introduced

That's an orphaned package that has been removed from CRAN. Consider bit64: http://cran.r-project.org/web/packages/bit64/index.html or Rmpfr: http://cran.r-project.org/web/packages/Rmpfr/index.html — IRTFM, Oct 10 '14 at 15:36

score 8 · Accepted Answer · answered Oct 10 '14 at 15:57

For a number that large, you'll need to load a package that supports representations of arbitrarily large numbers. Rmpfr is one example:

library(Rmpfr)

## Check that it works as expected on smaller numbers:
strtoi("ff", base=16)
# [1] 255
mpfr("ff", base=16)
# 1 'mpfr' number of precision  8   bits 
# [1] 255
as.integer(mpfr("ff", base=16)
# [1] 255

## Then apply it with (more) confidence to larger numbers: 
mpfr("7f2d36a2a000", base=16)
# 1 'mpfr' number of precision  48   bits 
# [1] 139832166883328
mpfr("7f2d36a2a0007f2d36a2a0007f2d36a2a0007f2d36a2a000", base=16)
# 1 'mpfr' number of precision  192   bits 
# [1] 3118361524223520784583964884878580812558070356334996529152

score 7 · Answer 2 · answered Oct 10 '14 at 16:32

7

Here's a way using bit64.

library(bit64)
str <- "7f2d36a2a000"
as.integer64(as.numeric(paste0("0x",str)))
# integer64
[1] 139832166883328

answered Oct 10 '14 at 16:32

jlhoward

58,004
7
97
140

4

Careful with this. `as.numeric` is double precision and has only 53 precision bits. So it might introduce rounding errors in the last digits! – Davor Josipovic Dec 11 '19 at 18:51

How do I convert 64-bit hexadecimal strings in R?

2 Answers2

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