Ruby regexp for replace some sequence

Question

How I can convert string -

text = "test test1 \n \n \n \n \n \n \n \n \n \n \n \n \n \n test2 \n"

to

test test1 \n\n\n\n\n\n\n\n\n\n\n\n\n\n test2\n

I tried use next - text.gsub(/\\s\\n/, '\\n') , but it added additional slash -

test test1\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n test2\\n

Answer 1

Use double quotes, instead of single:

text.gsub(/\s\n/, "\n")

With single quotes, \\n has the meaning of \\ and n , one after another. With double, it is interpreted as new line.

Answer 2

I expect that either the space after "test1" is to be removed as well or the space after "test2" is not to be removed. @ndn assumed the former was intended. If the second interpretation applies, you could do the following:

r = /
    (?<=\n) # match \n in a positive lookbehind
    \s      # match a whitespace character
    (?=\n)  # match \n in a positive lookahead
    /x      # extended/free-spacing regex definition mode

text.gsub(r,"")
    #=> "test test1 \n\n\n\n\n\n\n\n\n\n\n\n\n\n test2 \n"

or:

text.gsub(/\n\s(?=\n)/, "\n")