**From:** Martin Maechler (*maechler@stat.math.ethz.ch*)

**Date:** Thu 15 Apr 2004 - 22:55:09 EST

**Next message:**Douglas Bates: "Re: [R] Use R function in C code"**Previous message:**Jim Lemon: "Re: [R] summary(difftime(...))"**In reply to:**Samuel Edward Kemp: "[R] binary numbers"

Message-id: <16510.34349.928143.242715@gargle.gargle.HOWL>

*>>>>> "Samuel" == Samuel Edward Kemp <sam.kemp2@ntlworld.com>
*

*>>>>> on Wed, 14 Apr 2004 22:20:24 +0100 writes:
*

Samuel> Hi, Is there a function in R that lets one represent

Samuel> an integer in binary format for a given number of

Samuel> bits? So an example would be....

* >> binary.function(num=5, num.of.bits=8) "00000101"
*

Samuel> Or, is this something I have to write myself?

no. In package "sfsmisc", there's also

*>> digitsBase package:sfsmisc R Documentation
*

*>>
*

*>> Digit/Bit Representation of Integers in any Base
*

*>>
*

*>> Description:
*

*>>
*

*>> Compute the vector of "digits" A of the 'base' b representation of
*

*>> a number N, N = sum(k = 0:M ; A[M-k] * b^k).
*

*>>
*

*>> Usage:
*

*>>
*

*>> digitsBase(x, base = 2, ndigits = 1 + floor(log(max(x), base)))
*

e.g.,

*> library(sfsmisc) # after installing it
*

*> digitsBase(5, base= 2, 10)
*

[,1]

[1,] 0

[2,] 0

[3,] 0

[4,] 0

[5,] 0

[6,] 0

[7,] 0

[8,] 1

[9,] 0

[10,] 1

*> empty.dimnames(digitsBase(0:33, 2)) # binary
*

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0

0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0

0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0

0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0

0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

where you see that it does work vectorized.

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**Next message:**Douglas Bates: "Re: [R] Use R function in C code"**Previous message:**Jim Lemon: "Re: [R] summary(difftime(...))"**In reply to:**Samuel Edward Kemp: "[R] binary numbers"

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