convert large integers to hex

library(rSymPy)

sympy("hex(12345)")

format.hexmode(as.numeric(12345))

sympy("hex(6595137340052185552)")

Hi,

I'm wondering if someone has solved the problem of converting very
large integers to hex. I know about format.hexmode and as.hexmode, but
these rely on integers. The numbers I'm working with are overflowing
and losing precision. Here's an example:

x <- "6595137340052185552" # stored as character
as.integer(x) # warning about inaccurate conversion
format.hexmode(as.numeric(x)) # warnings about loss of precision
as.hexmode(x) # more warnings and does not do what I expected

I'm planning on writing a function that will do this, but would like
to know if anybody already has a solution. Basically, I would like the
functionality of format.hexmode on arbitrarily large integers.

Thanks,

--sundar

source("http://r-bc.googlecode.com/svn/trunk/R/bc.R")
bc("obase = 16; 123456789123456789", retclass = "character")

You can use the 'bc' command (use Cygwin if on Windows);

/cygdrive/c: bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
x=6595137340052185552
obase=16
x
5B86A277DEB9A1D0

You can call this from R.

On Wed, May 6, 2009 at 3:26 PM, Sundar Dorai-Raj <sdorairaj at gmail.com>wrote:

Hi,

I'm wondering if someone has solved the problem of converting very
large integers to hex. I know about format.hexmode and as.hexmode, but
these rely on integers. The numbers I'm working with are overflowing
and losing precision. Here's an example:

x <- "6595137340052185552" # stored as character
as.integer(x) # warning about inaccurate conversion
format.hexmode(as.numeric(x)) # warnings about loss of precision
as.hexmode(x) # more warnings and does not do what I expected

I'm planning on writing a function that will do this, but would like
to know if anybody already has a solution. Basically, I would like the
functionality of format.hexmode on arbitrarily large integers.

Thanks,

--sundar

--
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

? ? ? ?[[alternative HTML version deleted]]

There is an interface between R and bc -- not on CRAN but available
from its home page here:
http://r-bc.googlecode.com

source("http://r-bc.googlecode.com/svn/trunk/R/bc.R")
bc("obase = 16; 123456789123456789", retclass = "character")

[1] "1B69B4BACD05F15"


On Wed, May 6, 2009 at 9:59 PM, jim holtman <jholtman at gmail.com> wrote:

You can use the 'bc' command (use Cygwin if on Windows);

/cygdrive/c: bc
bc 1.06
Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
x=6595137340052185552
obase=16
x
5B86A277DEB9A1D0

You can call this from R.

On Wed, May 6, 2009 at 3:26 PM, Sundar Dorai-Raj <sdorairaj at gmail.com>wrote:

Hi,

I'm wondering if someone has solved the problem of converting very
large integers to hex. I know about format.hexmode and as.hexmode, but
these rely on integers. The numbers I'm working with are overflowing
and losing precision. Here's an example:

x <- "6595137340052185552" # stored as character
as.integer(x) # warning about inaccurate conversion
format.hexmode(as.numeric(x)) # warnings about loss of precision
as.hexmode(x) # more warnings and does not do what I expected

I'm planning on writing a function that will do this, but would like
to know if anybody already has a solution. Basically, I would like the
functionality of format.hexmode on arbitrarily large integers.

Thanks,

--sundar

--
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

? ? ? ?[[alternative HTML version deleted]]