Removing “\n” from string
Question
When I save the output of a bash command (executed in backticks) to an instance variable, the browser, or more specifically, the variable, removes the "\\n" characters. I checked the source code of the page, and it displays like this:
line 1
line 2
line 3
line 4
line 5
line 6
line 7
line 8
line 9
line 10
But the browser displays it like this:
line 1 line 2 line 3 line 4 line 5 line 6 line 7 line 8 line 9 line 10
I put this on a method that displays the output:
@variable.each_line do |line|
if line !~ /word1| word2/
line.sub("Word_I_don't_want", '')
end
end
But the variable won't be compared to the regular expression, and is printed as a whole. The browser displays a string without <br> as a single line, but the source code shows that new lines are being identified, but not processed. I tried
line.sub("\n", "<br>")
but it didn't work either. Hope someone has some tips for me.
SOLVED:
Thanks to ilan berci I could print the desired values, although the Tin Man pointed out that text should be processed on the controller. So I modified my method:
tempString = String.new
@redes.each_line do |line|
if line !~ /word1|word2/
tempString = tempString + line.sub("word_I_don't_want", "").sub("\n", "<br>")
end
end
@redes = tempString
Because processing the text in the .erb was filling the page code with <br> for every unwanted line (the <br> was casted in every .each_line iteration).
Thanks for the help!
4 answers
solution1
1 ACCPTED 2014-02-25 15:41:15
<% @variable.each_line do |line| %>
<% line = if line !~ /word1| word2/ %>
<%line.sub("Word_I_don't_want", '') %>
<% end %>
<%= line %>
<br/>
<% end %>
solution2
1 2014-02-25 16:01:39
The problem is how browsers display line-ends and white-space. They "gobble" spaces, tabs, vertical-tabs and line-endings, squeezing them into a single space when displayed.
For instance:
<html>
<body>
foo
bar
</body>
</html>
Will display as foo bar in a browser, even though there is line-end ("\\n") between foo and bar .
You can fix that a couple ways:
<html>
<body>
foo<br>
bar<br>
</body>
</html>
Or:
<html>
<body>
<pre>
foo
bar
</pre>
</body>
</html>
would display as:
foo
bar
Whereas:
<html>
<body>
<p>foo</p>
<p>bar</p>
</body>
</html>
would display as:
foo
bar
Browser barely honor whitespace. Words with multiple spaces and line-ends will display as if they only have a single space. If I had a string of characters:
foo\t \n bar
in a page, they would display as:
foo bar
because the browser is trying to be helpful.
How do you "fix" your code? You either wrap your text in a <pre> block, append <br> to the lines where you want line-breaks, or do something fun with CSS to adjust the defaults of <p> or <div> tags. There are lots of ways to get there, you just need to know what you're working with and pick a path.
solution3
0 2014-02-25 15:35:44
I've used this in my applications:
def replace_newlines_with_br_tags(text)
h(text).gsub(/\r\n/, '<br />').gsub(/\r/, '<br />').gsub(/\n/, '<br />')
end
You can add this to your application helper and use it in your views, etc.
solution4
0 2014-02-25 15:42:18
@variable.gsub(/(?:\n\r?|\r\n?)/, '<br>')
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