preg_replace removes multiple "\n"s

Question

How do I remove multiple occurrences of \n from the sample below and replace with just one occurrence of \n?

Basically I just want to remove multiple line breaks and replace them with just one line break.

\n\n\n\n\n\n\n\n \n\n \n\n\n\n\n\n\n    \n\n     \n\n     \n\n    \n\n    \n\n     \n\n     \n\n     \n     \n     \n     \n     \n     \n     \n\n     \n\n     \n\n     \nEDITION:  U.S.\n\n \nINTERNATIONAL\n\n     \nMÉXICO\n\n     \n\n     \nSet edition preference\n\n     \n\n     \n\n     \n\n     \nSign up\n\n     \nLog in\n\n     \n\n \n\n     \n\n     \n\n     \n\n\n\n\n\n\n\n\n\n\n\n     \n\n     \n\n\n \n\n \n\n     \n\n     \n\n    \n\n    \n\n     \n\n     \nHome\n\n     \nVideo\n\n     \nNewsPulse\n\n \nU.S.\n\n     \nWorld\n\n     \nPolitics\n\n     \nJustice\n\n     \nEntertainment\n\n     \nTech\n\n     \nHealth\n\n     \nLiving\n\n     \nTravel\n\n \nOpinion\n\n     \niReport\n\n     \nMoney\n\n     \nSports\n\n     \n\n    \n\n\n\n\n\n \n\n\n\n\n\n\n\n \n\n\n\n \n\n\n\n\n\n\n \n\nupdated 10:02 a.m.EDT, Fri June 3, 2011\n\n\n\n\n\n \n\n\n\n\n\nDr. Jack Kevorkian dead at 83\n\n\n\n\n\n\nThe Michigan pathologist who put assisted suicide on the world\'s medical ethics stage, apparently died of a blood clot, according to his attorney. FULL STORY

PeterT I just tried your method, but now nothing is returned. idk why. — Dylan, Jun 03 '11 at 14:32
What code are you using to replace with. PeterT has the right regex for this AFAIK — Mitch Grande, Jun 03 '11 at 14:33
I need the multiple lines replaced with a single line, mario. So newlines I suppose. — Dylan, Jun 03 '11 at 14:34
PHP. current code is: echo $archive = preg_replace("[\n]+", "\n", $archive); — Dylan, Jun 03 '11 at 14:34
Seems like you just forgot the [PCRE delimiters](http://www.php.net/manual/en/regexp.reference.delimiters.php) then. — mario, Jun 03 '11 at 14:35

score 3 · Answer 1 · edited Jul 04 '19 at 19:51

3

Two ways

while(strpos($string, "\n\n") !== false)
  str_replace("\n\n", "\n", $string);

And

preg_replace("/\n+/", "\n", $string);

edited Jul 04 '19 at 19:51

Peter Mortensen

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answered Jun 03 '11 at 14:35

dynamic

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In my framework I am currently using hte first version because when I wrote it 6 years ago didn't know much about regex XD (I was kiddish too) – dynamic Jun 03 '11 at 15:35

score 2 · Answer 2 · answered Jun 03 '11 at 14:37

2

This should work:

<?php
$string = "\n\n\n\n Text \n\n Text \n\n\n\n\n Text \n\n\n";

echo preg_replace("#[\n]+#", "\n", $string);

answered Jun 03 '11 at 14:37

Jim

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Oh well :) Yours shows it without, so its all good. Thanks for the fyi though. – Jim Jun 03 '11 at 16:15

score 1 · Answer 3 · edited Jul 04 '19 at 19:51

1

If this is a real carriage return you can do this to remove successive carriage returns:

preg_replace('/\n+/', '\n', $yourString);

Else for the string '\n' you can do:

preg_replace('/(\\n)+/', '\n', $yourString);

Finally, if you want to remove all spaces in between your \n too you can do"

preg_replace('/\s*\n+/', '\n', $yourString);

edited Jul 04 '19 at 19:51

Peter Mortensen

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answered Jun 03 '11 at 14:35

malko

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For a linebreak to work, you need to enclose it in double quotes on at least the replaced part, IE `"\n"`. – Jim Jun 03 '11 at 14:39
The `\n` in the single quoted regex are correct (more advisable to have PCRE interpret the escape sequences). But the replacement string must indeed be filled by PHP with the correct character sequences. – mario Jun 03 '11 at 14:42
only for the second case where we want to replace string '\n' we should keep the replacement part as single quote, others require double quotes. – malko Jun 03 '11 at 14:44

score 1 · Answer 4 · edited Jul 04 '19 at 19:52

1

Try forcing the + match to be greedy, by using ++ instead.

preg_replace('/\n++/', "\n", $yourString);

edited Jul 04 '19 at 19:52

Peter Mortensen

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answered Jun 03 '11 at 14:40

Lethargy

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Problem you will have is you need `"` around the replacement `\n` for it to return a new line character. – Jim Jun 03 '11 at 14:46
Oh whoops. Sorry I Just copied it from another example without properly looking :P – Lethargy Jun 03 '11 at 14:58

score 0 · Answer 5 · answered Jun 25 '12 at 08:05

Strange, none of the code works? Example:

$barcodes = "5312353123123



5312353123123



5312353123123";
echo(     var_dump(   $barcodes     )     . '</br>' . "\n"  );
$barcodes = preg_replace('/\n+/', "\n", $barcodes);
exit(  var_dump(   $barcodes     )     . '</br>' . "\n"  );

Output:

string(55) "5312353123123 5312353123123 5312353123123"
string(55) "5312353123123 5312353123123 5312353123123"

That means the function does... nothing?

score 0 · Answer 6 · answered Feb 19 '14 at 17:18

0

Another way from the gotcha's examples on the man page for str_replace() is:

// Order of replacement
$str     = "Line 1\nLine 2\rLine 3\r\nLine 4\n";
$order   = array("\r\n", "\n", "\r");
$replace = '<br />';

// Processes \r\n's first so they aren't converted twice.
$newstr = str_replace($order, $replace, $str);

answered Feb 19 '14 at 17:18

Sanford Staab

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FYI: `\R` is much more compact than `array("\r\n", "\n", "\r")` and have the same meaning. – Toto Feb 19 '14 at 17:47

score 0 · Answer 7 · edited Oct 26 '15 at 11:01

0

Try:

$newstr = preg_replace("/\r\n\r\n|\r\r|\n\n/", "..", $str);

edited Oct 26 '15 at 11:01

kenorb

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answered Oct 26 '15 at 08:49

tashi

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preg_replace removes multiple "\n"s

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