Replace "&" to "\&" in Ruby seems impossible?

Question

I want to replace all & characters into \& with String.gsub (or a other method). I've tried several combinations and read another question here, but nothing is gonna work.

  "asdf & asdf".gsub("&", "\\\&") => "asdf & asdf"

Answer 1

Your linked question provides a solution - use the block form of gsub:

irb(main):009:0> puts "asdf & asdf".gsub("&"){'\&'}
asdf \& asdf

Answer 2

ruby-1.9.2-p180 :008 > puts "asdf & asdf".gsub(/&/, '\\\&')
asdf \& asdf