Formatting binary values in Scala

I don't know of a direct API method to do it, but here is one way of doing it:

def toBinary(i: Int, digits: Int = 8) =
    String.format("%" + digits + "s", i.toBinaryString).replace(' ', '0')

scala> 3.toBinaryString
res0: String = 11

Scala has an implicit conversion from Int to RichInt which has a method toBinaryString. This function does not print the leading zeroes though.