I have this string:
"some text\nandsomemore"
I need to remove the "\n" from it. I've tried
"some text\nandsomemore".gsub('\n','')
but it doesn't work. How do I do it? Thanks for reading.
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7 Answers
You need to use "\n" not '\n' in your gsub. The different quote marks behave differently.
Double quotes " allow character expansion and expression interpolation ie. they let you use escaped control chars like \n to represent their true value, in this case, newline, and allow the use of #{expression} so you can weave variables and, well, pretty much any ruby expression you like into the text.
While on the other hand, single quotes ' treat the string literally, so there's no expansion, replacement, interpolation or what have you.
In this particular case, it's better to use either the .delete or .tr String method to delete the newlines.
4 Comments
boulder_ruby
proper syntax would really be .gsub(/\n/, "")
ocodo
@David is correct. However, I felt that it was important to show that the quotes make a difference, since that would benefit Ben at this point. Mind you, David, it's probably more of a matter of style than "correct". Personally I think
tr is a better choice for this task, but as I say, I thought it better to point out the difference in single, double quotes when I answered.
Juan José Ramírez
why is it better to use
.delete or .tr ?ocodo
They're faster than
.gsub because they do less (.delete would very likely be fastest, although a performance profiling would be good to 100% confirm this.)If you want or don't mind having all the leading and trailing whitespace from your string removed you can use the strip method.
" hello ".strip #=> "hello"
"\tgoodbye\r\n".strip #=> "goodbye"
as mentioned here.
edit The original title for this question was different. My answer is for the original question.
3 Comments
myconode
This does not answer the question.
strip only removes leading and trailing whitespace: ruby-doc.org/core-1.9.3/String.html#method-i-strip-21
ThomasW
@mvdanj Yes, given the details of this particular question it doesn't answer it, but it does answer the question just based on the title. I suspect that is why people have found it useful.
ThomasW
The title was changed from the time when I originally answered.
When you want to remove a string, rather than replace it you can use String#delete (or its mutator equivalent String#delete!), e.g.:
x = "foo\nfoo"
x.delete!("\n")
x now equals "foofoo"
In this specific case String#delete is more readable than gsub since you are not actually replacing the string with anything.
2 Comments
Brent Dillingham
In Ruby 1.9.3 at least,
delete is not destructive as indicated here. It returns a new string.
Paul Leader
Well spotted. I've updated that code snippet to use the mutator version String#delete! rather than String#delete
You don't need a regex for this. Use tr:
"some text\nandsomemore".tr("\n","")
3 Comments
Arnold Roa
what is the difference between tr an replace?
Mark Thomas
replace just changes the string to a new one, like variable assignment; whereas tr is a character-by-character global find and replace.
Matrix
and the difference with gsub?
use chomp or strip functions from Ruby:
"abcd\n".chomp => "abcd"
"abcd\n".strip => "abcd"
2 Comments
myconode
This does not answer the question.
strip only removes leading and trailing whitespace - ruby-doc.org/core-1.9.3/String.html#method-i-strip-21
silva96
in chomp method, \n and \r are removed from the end of str if they exist, not in the middle. So this doesn't solve OP question
#squish will remove all spacing including newlines and tabs.
"some text\nandsomemore".squish #=> "some textandsomemore"
"some text\nand\n\n\n\n\some \t\tmore".squish #=> "some textandsomemore"
1 Comment
NGobin
Squish is great, and probably what you actually want in many cases. Two points though: (1) squish is a rails method, not ruby, and (2) it will replace a newline character with whitespace, so the output would actually be
"some text andsomemore" in the first case, and "some text and ome more" in the second (the \s at the start of "some" is a whitespace character)for some reason none of those answer works in my case, I figured out my own solution:
3.1.2 :003 > "some text\nandsomemore".split.join(' ')
=> "some text andsomemore"
2 Comments
josemigallas
This returns
sometextandsomemore, so not at all what is being asked here.
William Herry
@josemigallas my mistake, you should use a delimiter when join, the answer has been updated