Create binary vector of a given number

Question

Is there an easy way to get a binary vector of a number? I would like to specify the number of bits to use.

So, for example, 4 in 4bit would return c(F,T,F,F) or in 6bit c(F,F,F,T,F,F).

So what I want to create is something like this but with about 8 factors (tx)

library(ggplot2)
tx <- factor(c("a", "b", "c"))
ty <- rep(0:(2 ^ length(tx) - 1), each=length(tx))
df <- data.frame(x=tx, y=ty)
df$z <- c(F,F,F,F,F,T,F,T,F,F,T,T,T,F,F,T,F,T,T,T,F,T,T,T)
ggplot(df, aes(x, y, fill = z)) + geom_raster()

Could anybody help me with this?

alexis_laz · Accepted Answer · 2014-11-14 12:28:47Z

2

Something like this, also, seems valid:

ff = function(x, n) rev(as.logical(intToBits(x))[seq_len(n)])

ff(4, 4)
#[1] FALSE  TRUE FALSE FALSE
ff(4, 6)
#[1] FALSE FALSE FALSE  TRUE FALSE FALSE

Vectorize(ff)(c(4,9,10,0,5), 6)  ##to compare with akrun's
#      [,1]  [,2]  [,3]  [,4]  [,5]
#[1,] FALSE FALSE FALSE FALSE FALSE
#[2,] FALSE FALSE FALSE FALSE FALSE
#[3,] FALSE  TRUE  TRUE FALSE FALSE
#[4,]  TRUE FALSE FALSE FALSE  TRUE
#[5,] FALSE FALSE  TRUE FALSE FALSE
#[6,] FALSE  TRUE FALSE FALSE  TRUE

answered Nov 14, 2014 at 12:28

alexis_laz

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1 Comment

drmariod Over a year ago

Really nice solution an much easier to read! Thanks for this!

akrun · Accepted Answer · 2014-11-14 09:00:20Z

2

Try

as.logical(rep(4,each=4)%/% (2^(3:0)) %%2)
#[1] FALSE  TRUE FALSE FALSE

as.logical(rep(4,each=6)%/% (2^(5:0)) %%2)
#[1] FALSE FALSE FALSE  TRUE FALSE FALSE


v1 <- c(4,9,10,0,5)
!!matrix(rep(v1,each=6)%/% (2^(5:0)) %%2, ncol=6, byrow=TRUE)
#      [,1]  [,2]  [,3]  [,4]  [,5]  [,6]
#[1,] FALSE FALSE FALSE  TRUE FALSE FALSE
#[2,] FALSE FALSE  TRUE FALSE FALSE  TRUE
#[3,] FALSE FALSE  TRUE FALSE  TRUE FALSE
#[4,] FALSE FALSE FALSE FALSE FALSE FALSE
#[5,] FALSE FALSE FALSE  TRUE FALSE  TRUE

answered Nov 14, 2014 at 9:00

akrun

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