What is the best way to chop a string into chunks of a given length in Ruby?

Question

I have been looking for an elegant and efficient way to chunk a string into substrings of a given length in Ruby.

So far, the best I could come up with is this:

Answer 1

I made a little test that chops about 593MB data into 18991 32KB pieces. Your slice+map version ran for at least 15 minutes using 100% CPU before I pressed ctrl+C. This version using String#unpack finished in 3.6 seconds:

def chunk(string, size)
  string.unpack("a#{size}" * (string.size/size.to_f).ceil)
end