Replace new line/return with space using regex

Question

Pretty basic question for someone who knows.

Instead of getting from

"This is my text. 

And here is a new line"

To:

"This is my text. And here is a new line"

I get:

"This is my text.And here is a new line.

Any idea why?

L.replaceAll("[\\\t|\\\n|\\\r]","\\\s");

I think I found the culprit.

On the next line I do the following:

L.replaceAll( "[^a-zA-Z0-9|^!|^?|^.|^\\s]", "");

And this seems to be causing my issue.

Any idea why?

I am obviously trying to do the following: remove all non-chars, and remove all new lines.

Could you just do `L.replaceAll("[\\\t|\\\n|\\\r]"," ");`? – benjer3 Jun 15 '12 at 10:33 — benjer3, Jun 15 '12 at 10:33
i tried and this appears to not work. – jason m Jun 15 '12 at 10:37 — jason m, Jun 15 '12 at 10:37

score 72 · Answer 1 · edited Aug 16 '17 at 12:11

72

\s is a shortcut for whitespace characters in regex. It has no meaning in a string. ==> You can't use it in your replacement string. There you need to put exactly the character(s) that you want to insert. If this is a space just use " " as replacement.

The other thing is: Why do you use 3 backslashes as escape sequence? Two are enough in Java. And you don't need a | (alternation operator) in a character class.

L.replaceAll("[\\t\\n\\r]+"," ");

Remark

L is not changed. If you want to have a result you need to do

String result =     L.replaceAll("[\\t\\n\\r]+"," ");

Test code:

String in = "This is my text.\n\nAnd here is a new line";
System.out.println(in);

String out = in.replaceAll("[\\t\\n\\r]+"," ");
System.out.println(out);

edited Aug 16 '17 at 12:11

JeanValjean

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answered Jun 15 '12 at 10:38

stema

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`L.replaceAll("[\\t|\\n|\\r]"," ");` also appears to not work though. – jason m Jun 15 '12 at 10:39
1

You might want to add a `+` after the character class, so you only get one space for each sequence of whitespace characters. – Tim Pietzcker Jun 15 '12 at 10:43
@jasonm I updated my solution. The changed string is **returned**, `L` is not changed. Is this your problem? – stema Jun 15 '12 at 10:50
` //How to remove all new and reutnrs String _L = L.replaceAll("[\\r?\\n|\\t]+"," "); //Normalize for all noncharss _L = _L.replaceAll( "[^a-zA-Z0-9|^!|^?|^.|^\\s]", ""); //Normalize for the sentences _L = _L.replaceAll("[?|!]", ".");` – jason m Jun 15 '12 at 10:51
the above are the three lines of code i am using the clean the results. – jason m Jun 15 '12 at 10:51
@jasonm, I think you need to clarify your question (within your question, not as comment) and explain what you want to achieve, what is the expected output? – stema Jun 15 '12 at 11:00

Dimitar II · Answer 2 · 2019-02-03T20:51:02.633

15

The new line separator is different for different OS-es - '\r\n' for Windows and '\n' for Linux.

To be safe, you can use regex pattern \R - the linebreak matcher introduced with Java 8:

String inlinedText = text.replaceAll("\\R", " ");

edited Feb 03 '19 at 20:51

answered Jan 01 '19 at 16:01

Dimitar II

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Nice! Although to replace linebreak and spurious whitespace introduced by indentation? \R[\s]{2,} ? – ndtreviv Jun 08 '22 at 12:27

Keppil · Answer 3 · 2012-06-15T10:46:26.983

10

Try

L.replaceAll("(\\t|\\r?\\n)+", " ");

Depending on the system a linefeed is either \r\n or just \n.

edited Jun 15 '12 at 10:46

answered Jun 15 '12 at 10:42

Keppil

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This is wrong. `?` means a literal question mark in a character class (just as `|` is a literal here too). And four backslashes are overkill, even for Java. EDIT: But that's @adarshr's fault for not taking out the extra backslashes when reformatting the answer :) – Tim Pietzcker Jun 15 '12 at 10:44
Oh, sorry, I didn't realise that. Glad it is fixed now. – adarshr Jun 15 '12 at 10:52
Thanks for this alternative answer. I was trying to solve a similar problem - replacing all OS' newlines with my host's standard newline, and this approach can be adapted for that problem - here's the regex: "(\\r?\\n)+" – Ian Durkan Aug 22 '13 at 22:21
@Keppli I extended your way by `|\\n`, so no matter which kind of linefeed does exists. – Reporter Feb 19 '14 at 14:01

buckley · Answer 4 · 2012-06-16T09:54:21.297

3

Your regex is good altough I would replace it with the empty string

String resultString = subjectString.replaceAll("[\t\n\r]", "");

You expect a space between "text." and "And" right?

I get that space when I try the regex by copying your sample

"This is my text. "

So all is well here. Maybe if you just replace it with the empty string it will work. I don't know why you replace it with \s. And the alternation | is not necessary in a character class.

edited Jun 16 '12 at 09:54

answered Jun 15 '12 at 10:40

buckley

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I'm not doing jave but is it realy necessary to put an extra escape characters like \\t ? Isn't \t enough? – buckley Jun 15 '12 at 10:41
I think for `\t`, `\r` and `\n` you will get away with a single backslash. The regex engine will then not be given the string `\n` (which it would internally interpret as a newline character) but the newline character directly (0x0A, I think). But since all other backslashes in regexes do need to be doubled (`\s` or `\b` for example), it's convention to always use double backslashes. – Tim Pietzcker Jun 15 '12 at 10:52
@jasonm Can you save your file so we can download it? That will certainly allow us to diagnose what's going on – buckley Jun 15 '12 at 13:23
...and again, the `|` does not belong there. There's no need to specify OR in a character class, so `|` just matches a literal `|`. – Alan Moore Jun 16 '12 at 02:23
@AlanMoore Of course, alternation is not necessary in a char class – buckley Jun 16 '12 at 09:54

score 3 · Answer 5 · edited May 23 '17 at 12:25

I found this.

String newString = string.replaceAll("\n", " ");

Although, as you have a double line, you will get a double space. I guess you could then do another replace all to replace double spaces with a single one.

If that doesn't work try doing:

string.replaceAll(System.getProperty("line.separator"), " ");

If I create lines in "string" by using "\n" I had to use "\n" in the regex. If I used System.getProperty() I had to use that.

Ishwar · Answer 6 · 2013-11-27T06:42:51.650

0

You May use first split and rejoin it using white space. it will work sure.

String[] Larray = L.split("[\\n]+");
L = "";
for(int i = 0; i<Larray.lengh; i++){
   L = L+" "+Larray[i];  
}

edited Nov 27 '13 at 06:42

answered Nov 27 '13 at 06:20

Ishwar

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score 0 · Answer 7 · answered Aug 20 '20 at 05:37

0

This should take care of space, tab and newline:

data = data.replaceAll("[ \t\n\r]*", " ");

answered Aug 20 '20 at 05:37

Ani Menon

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Replace new line/return with space using regex

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