Converting between bases (binary and hexadecimal)

This lesson covers converting between bases in R, with the aim of deepening your understanding of how numbers are represented inside a computer.

R has no dedicated function for binary conversion, so you implement it yourself by repeatedly dividing and taking the remainder. Hexadecimal is straightforward with sprintf("%x", value).

In the sample code, to_binary() builds each binary digit by repeatedly taking the remainder with n %% 2 and the quotient with n %/% 2. Note how simply sprintf("%x", 42) handles hexadecimal by comparison.

A common early stumble is precisely that absence of a standard binary function. Most languages provide one, so having to write the algorithm yourself in R is a surprise.

Binary is used inside the computer and hexadecimal in things like colour codes — basic knowledge worth having.

📖 Reference code

to_binary <- function(n) {
  if (n == 0) return("0")
  bits <- c()
  while (n > 0) {
    bits <- c(n %% 2, bits)
    n <- n %/% 2
  }
  paste(bits, collapse = "")
}

cat(to_binary(42), "\n")
cat(sprintf("%x", 42), "\n")
cat(strtoi("101010", base = 2), "\n")

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run R directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).