CODEWITHSUNDEEP
rubystring
user938363
user938363

Reputation: 10350

How to add string "\n" literally at the end of each line in Ruby?

Here is a string str:

str = "line1
       line2
       line3"

We would like to add string "\n" to the end of each line:

str = "line1 \n
       line2 \n
       line3 \n"

A method is defined:

   def mod_line(str)
     s = ""
     str.each_line do |l|
       s += l + '\\n'
     end
   end

The problem is that '\n' is a line feed and was not added to the end of the str even with escape \. What's the right way to add '\n' literally to each line?

Upvotes: 1

Views: 1561

Answers (4)

Aleksei Matiushkin
Aleksei Matiushkin

Reputation: 121000

The platform-independent solution:

str.gsub(/\R/) {  " \\n#{$~}" }

It will search for line-feeds/carriage-returns and replace them with themselves, prepended by \n.

Upvotes: 3

cremno
cremno

Reputation: 4927

String#gsub/String#gsub! plus a very simple regular expression can be used to achieve that:

str = "line1
       line2
       line3"
str.gsub!(/$/, ' \n')
puts str

Output:

line1 \n
       line2 \n
       line3 \n

Upvotes: 3

CheeseFry
CheeseFry

Reputation: 1319

This is the closest I got to it. 

def mod_line(str)
         s = ""
     str.each_line do |l|
           s += l
     end
         p s
   end

Using p instead of puts leaves the \n on the end of each line.

Upvotes: 1

sawa
sawa

Reputation: 168101

\n needs to be interpreted as a special character. You need to put it in double quotes.

"\n"

Your attempt:

'\\n'

only escapes the backslash, which is actually redundant. With or without escaping on the backslash, it gives you a backslash followed by the letter n.

Also, your method mod_line returns the result of str.each_line, which is the original string str. You need to return the modified string s:

def mod_line(str)
  ...
  s
end

And by the way, be aware that each line of the original string already has "\n" at the end of each line, so you are adding the second "\n" to each line (making it two lines).

Upvotes: 1

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