How to convert integer number into binary vector?


How to convert an integer number into binary vector using R?

For example :

number <- 11
[1] 1 0 1 1

what is the fastest possible method of conversion (using R code or some existing functions from packages) if I need to convert whole vector of numbers (minimum value = 0, maximum =300) into binary matrix ?

Follow the rabbit : base::intToBits



There's the intToBits function that converts any integer to a vector of 32 raws, so you can do this:

decimals <- c(3,5,11,4)
m <- sapply(decimals,function(x){ as.integer(intToBits(x))})
m

> m
      [,1] [,2] [,3] [,4]
 [1,]    1    1    1    0
 [2,]    1    0    1    0
 [3,]    0    1    0    1
 [4,]    0    0    1    0
 [5,]    0    0    0    0
 [6,]    0    0    0    0
 [7,]    0    0    0    0
 [8,]    0    0    0    0
 [9,]    0    0    0    0
[10,]    0    0    0    0
[11,]    0    0    0    0
[12,]    0    0    0    0
[13,]    0    0    0    0
[14,]    0    0    0    0
[15,]    0    0    0    0
[16,]    0    0    0    0
[17,]    0    0    0    0
[18,]    0    0    0    0
[19,]    0    0    0    0
[20,]    0    0    0    0
[21,]    0    0    0    0
[22,]    0    0    0    0
[23,]    0    0    0    0
[24,]    0    0    0    0
[25,]    0    0    0    0
[26,]    0    0    0    0
[27,]    0    0    0    0
[28,]    0    0    0    0
[29,]    0    0    0    0
[30,]    0    0    0    0
[31,]    0    0    0    0
[32,]    0    0    0    0

This SO post suggests the intToBits function. I define the function number2binary, which includes an argument noBits to control how many bits are returned. Standard is to return 32 bits.

number2binary = function(number, noBits) {
       binary_vector = rev(as.numeric(intToBits(number)))
       if(missing(noBits)) {
          return(binary_vector)
       } else {
          binary_vector[-(1:(length(binary_vector) - noBits))]
       }
    }

And for some examples:

> number2binary(11)
 [1] 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 0 1 1
> number2binary(11, 4)
[1] 1 0 1 1

Try the CRAN package "binaryLogic"

library(binaryLogic)

as.binary(11)
[1] 1 0 1 1

as.binary(11, littleEndian=TRUE)
[1] 1 1 0 1

as.binary(42, n=16)
[1] 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0

as.binary(0:2, n=2)
[[1]]
[1] 0 0

[[2]]
[1] 0 1

[[3]]
[1] 1 0

as.binary(0xFF)
[1] 1 1 1 1 1 1 1 1

Also available: shift, rotate, graycode etc.