Regex PHP to find and replace white space and,or new line between HTML tags

Question

I will have a string (one line) composed by a HTML code that will be stored in a PHP variable. This string comes from a HTML page that normally has new line and white spaces between tags. We can have new line (one or more) and, or white space like this exemle:

<h1>tag1</h> 
       <p>Between h ad p we have \s and \n</p>

After perform a regex and preg_replace I would like to have this:

<h1>tag1</h><p>Between h ad p we have \s and \n</p>

I have tried this regex but it is not workig.

$str=<<<EOF
<h1>tag1</h> 
           <p>Between h ad p we have \s and \n</p>

EOF;


$string =  trim(preg_replace('/(>\s+<)|(>\n+<)/', ' ', $str));

Here you can find the entire code http://www.phpliveregex.com/p/7Pn

possible duplicate of [HTML minification?](http://stackoverflow.com/questions/728260/html-minification) — Glavić, Nov 01 '14 at 06:12
Hi Glavic, it could work, but I need the regex expression behind the scenes. This site do the job http://kangax.github.io/html-minifier/ — zwitterion, Nov 01 '14 at 06:20
See the footer: *Source and bugtracker are hosted on Github.* — Glavić, Nov 01 '14 at 06:26

nu11p01n73R · Accepted Answer · 2014-11-01T06:46:05.657

5

There are two problems with

(preg_replace('/(>\s+<)|(>\n+<)/', ' ', $str)

\s already includes \n hence there is no need to provide another alternation.
(>\s+<)here the regex consumes both the angulars < and > hence replacing with space would remove everything including the angulars

The output is

<h1>tag1</hp>Between h ad p we have \s and \n</p>

which is not what you want

How to correct

use the regex (>\s+<) and replacement string as >< giving output as

<h1>tag1</h><p>Between h ad p we have \s and \n</p>

for example http://regex101.com/r/dI1cP2/2

you can also use lookaround to solve the issue

the regex would be

(?<=>)\s+(?=<)

and replace string would be empty string

Explanation

(?<=>) asserts that \s is presceded by >

\s+ matches one or more space

(?=<) asserts the \s is followed by <

Here the look arounds will not consume any angular brackets as in the earlier regex

see http://regex101.com/r/dI1cP2/3 for example

edited Nov 01 '14 at 06:46

answered Nov 01 '14 at 06:39

nu11p01n73R

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Hi nu11p01n73R, infact there is a letter "g" (modifiers) outside the regex that makes the difference. So should we use like this inside a php code `preg_replace("/(>\s+ – zwitterion Nov 01 '14 at 13:08
There is no "g" modifiers in php http://php.net/manual/en/reference.pcre.pattern.modifiers.php – zwitterion Nov 01 '14 at 13:14
@zwitterion glad to hear it worked :) Hope you resolved the issues – nu11p01n73R Nov 01 '14 at 14:37
1

yes in fact, for preg_replace in php we dont need to use "g" modifier. thnks – zwitterion Nov 01 '14 at 15:44

score 0 · Answer 2 · answered Nov 01 '14 at 06:18

0

You can try with this:

echo preg_replace("/(?=\>\s+\n|\n)+(\s+)/", "", $str);

answered Nov 01 '14 at 06:18

jogesh_pi

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What if they use windows server? – ArtisticPhoenix Nov 01 '14 at 06:19
@ArtisiticPhoenix, Sorry i don't have experience with Windows Server yet, Can you ellaborate hows its not working on windows server? – jogesh_pi Nov 01 '14 at 06:20
A lot of times windows will use "\r\n" for the line ending. So just "\n" may not match. – ArtisticPhoenix Nov 01 '14 at 06:24

score 0 · Answer 3 · answered Nov 01 '14 at 06:22

0

(?<=<\/h>)\s+

Try this.See demo.Replace by empty string

http://regex101.com/r/jI8lV7/1

answered Nov 01 '14 at 06:22

vks

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Regex PHP to find and replace white space and,or new line between HTML tags

3 Answers3