ruby write newline character to file but do not interpret as a true newline

Question

I am trying to write a ruby string to a file in such a way that any newline characters embedded in the string remain embedded. This is being written out to a file which will then be processed by another tool.

An example is below.

I want this: 1 [label="this is a\ntest"] \n (second \n is a true newline)
I have tried this: string = '1 [label="this is a\ntest"]' + "\n"

Any thoughts?

Answer 1

I figured it out. I was using rails word_wrap helper function to wrap text and that was using "\n" and not '\n'. I copied the function and wrote my own.

Good to go now.

Answer 2

the first newline in the example above is read as a real newline by the downstream processing tool.

This sounds like your problem, then. Your processing tool is taking the literal whack-n (aka \x5c\x6e) and translating it to a single \x0a).

In other words, your output process is fine -- it's your input process is unsafe. You can check your string like so:

string.split(//).map {|x| x[0].ord.to_s(16)}

You'll notice there's only one "a" there, at the end.

Answer 3

In Ruby, single quotes don't interpret escape sequences. You could use the quote operator:

string = %Q/1 [label="this is a\\ntest"] \n/

The character after %Q is the string beginning, ending delimiter. ruby intelligently uses paired characters that have open close equivalents. e.g.

string = %Q{1 [label="this is a\\ntest"] \n}
string = %Q(1 [label="this is a\\ntest"] \n)
string = %Q!1 [label="this is a\\ntest"] \n!

This lets you choose a convenient delimiter doesn't need additional escaping for a particular string literal.