Converting decimal to binary in R?

Question

What would be the easiest way to convert a number to base 2 (in a string, as for example 5 would be converted to "0000000000000101") in R? There is intToBits, but it returns a vector of strings rather than a string:

> intToBits(12)  [1] 00 00 01 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [26] 00 00 00 00 00 00 00 

I have tried some other functions, but had no success:

> toString(intToBits(12)) [1] "00, 00, 01, 01, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00" 

Answer 1

paste(rev(as.integer(intToBits(12))), collapse="") does the job

paste with the collapse parameter collapses the vector into a string. You have to use rev to get the correct byte order though.

as.integer removes the extra zeros

Answer 2

Note that intToBits() returns a 'raw' vector, not a character vector (strings). Note that my answer is a slight extension of @nico's original answer that removes the leading "0" from each bit:

paste(sapply(strsplit(paste(rev(intToBits(12))),""),`[[`,2),collapse="") [1] "00000000000000000000000000001100" 

To break down the steps, for clarity:

# bit pattern for the 32-bit integer '12' x <- intToBits(12) # reverse so smallest bit is first (little endian) x <- rev(x) # convert to character x <- as.character(x) # Extract only the second element (remove leading "0" from each bit) x <- sapply(strsplit(x, "", fixed = TRUE), `[`, 2) # Concatenate all bits into one string x <- paste(x, collapse = "") x # [1] "00000000000000000000000000001100" 

Or, as @nico showed, we can use as.integer() as a more concise way to remove the leading zero from each bit.

x <- rev(intToBits(12)) x <- paste(as.integer(x), collapse = "") # [1] "00000000000000000000000000001100" 

Just for copy-paste convenience, here's a function version of the above:

dec2bin <- function(x) paste(as.integer(rev(intToBits(x))), collapse = "")