正则表达式的反向引用
s = "this is a test string" reg = /(is)/ s.gsub reg, "anything" 1.9.3-head :055 > $1 => "is" 1.9.3-head :055 > s.gsub reg, "\1 not" => "this is not a test string"
s = "this is a test string" reg = /(is)/ s.gsub reg, "anything" 1.9.3-head :055 > $1 => "is" 1.9.3-head :055 > s.gsub reg, "\1 not" => "this is not a test string"