How to remove carriage return using Ruby?

Question

I thought this code would work, but the regex never matches \ r \ n. I looked at the data that I am reading in the hex editor and checked that the file really has a hexadecimal D and a hexadecimal pattern.

I also tried the regular expressions / \ xD \ xA / m and / \ x0D \ x0A / m, but they also did not match.

This is my code right now:

lines2 = lines.gsub( /\r\n/m, "\n" ) if ( lines == lines2 ) print "still the same\n" else print "made the change\n" end 

In addition to the alternatives, it would be nice to know what I'm doing wrong (to make learning easier on my part). :)

Answer 1

What do you get when you do puts lines ? This will give you the key.

By default, File.open opens the file in text mode, so your \r\n characters will be automatically converted to \n . Perhaps the reason for lines always equal to lines2 . To prevent Ruby string parsing, use rb mode:

  C: \> copy con lala.txt
 a
 file
 with
 many
 lines
 ^ Z

 C: \> irb
 irb (main): 001: 0> text = File.open ('lala.txt'). read
 => "a \ nfile \ nwith \ nmany \ nlines \ n"
 irb (main): 002: 0> bin = File.open ('lala.txt', 'rb'). read
 => "a \ r \ nfile \ r \ nwith \ r \ nmany \ r \ nlines \ r \ n"
 irb (main): 003: 0>

But from your question and code, I see that you just need to open the file using the default modifier. You do not need any conversion and can use the shorter File.read .

Answer 2

Use String # strip

Returns a copy of str with leading and trailing spaces removed.

eg

 " hello ".strip #=> "hello" "\tgoodbye\r\n".strip #=> "goodbye" 

---

Using gsub

 string = string.gsub(/\r/," ") string = string.gsub(/\n/," ") 

Answer 3

Usually, when I am doing the removal of \ r or \ n, I will look for both, doing something like

 lines.gsub(/\r\n?/, "\n"); 

I found that depending on how the data was saved (OS used, editor used, Jupiter's relation to Io at that time), there may or may not be a new line after the carriage return. It seems strange that you see both characters in hex mode. Hope this helps.

Answer 4

 modified_string = string.gsub(/\s+/, ' ').strip 

Answer 5

 lines2 = lines.split.join("\n") 

Answer 6

"still the same\n".chomp
or
"still the same\n".chomp!

http://www.ruby-doc.org/core-1.9.3/String.html#method-i-chomp

Answer 7

If you use Rails, there is a squish way

"\tgoodbye\r\n".squish => "goodbye"

"\tgood \t\r\nbye\r\n".squish => "good bye"

Answer 8

What about the following?

 irb(main):003:0> my_string = "Some text with a carriage return \r" => "Some text with a carriage return \r" irb(main):004:0> my_string.gsub(/\r/,"") => "Some text with a carriage return " irb(main):005:0> 

Or...

 irb(main):007:0> my_string = "Some text with a carriage return \r\n" => "Some text with a carriage return \r\n" irb(main):008:0> my_string.gsub(/\r\n/,"\n") => "Some text with a carriage return \n" irb(main):009:0> 

Answer 9

Why not read the file in text mode and not in binary mode?

Answer 10

You can use this:

 my_string.strip.gsub(/\s+/, ' ') 

Answer 11

 lines.map(&:strip).join(" ") 

Answer 12

I think your regex is almost complete - this is what I will do:

 lines2 = lines.gsub(/[\r\n]+/m, "\n") 

In the above example, I put \ r and \ n in the class (so it doesn’t matter in which order they appear) and add the qualifier "+" (so that "\ r \ n \ r \ n \ r \ n "will also match once, and all this is replaced by" \ n ")