Lua: print integer as a binary

Question

How can I represent integer as Binary?

so I can print 7 as 111

Answer 1

local function tobinary( number )
  local str = ""
  if number == 0 then
      return 0
  elseif number < 0 then
      number = - number
      str = "-"
  end
  local power = 0
  while true do
      if 2^power > number then break end
      power = power + 1
  end
  local dot = true
  while true do
      power = power - 1
      if dot and power < 0 then
          str = str .. "."
          dot = false
      end
      if 2^power <= number then
          number = number - 2^power
          str = str .. "1"
      else
          str = str .. "0"
      end
      if number == 0 and power < 1 then break end
  end
  return str
end

May seem more verbose but it is actually faster than other functions that use the math library functions. Works with any number, be it positive/negative/fractional...