(?-si:<p class=".+?">|(?!\A)\G)(?s-i:(?!</p>).)*?\K\s+

General regex: (?-si:BSR|(?!\A)\G)(?s-i:(?!ESR).)*?\KFR

Why should you be believed over @guy038 ?

@guy038 said in Regex: How to remove enewline character from a particular html tags?:

Now, the generic variants, proposed by @Robin-cruise and @hellena-crainicu, with a final look-ahead only, containing the ESR region will not work, most of a time :-(

@Robin-cruise and @hellena-crainicu :

Be careful of posting simplifications.

Probably best to leave these things to the “Master”. :-)

Refering to my first blog post about a generic regex, below :

https://community.notepad-plus-plus.org/post/75007

and as Robin want to search for line-ending chars, we need to use, of course the complete generic regex S/R :

SEARCH (?-si:BSR|(?!\A)\G)(?s-i:(?!ESR).)*?\K(?-si:FR)

REPLACE RR

and not the simplified single-line version

So :

• The FR regex is just \R, as the non-capturing associated group, beginning with (?_si:..., is useless in this case

• The RR regex is \x20

• The BSR regex may be strictly the string <p class="mb-40px"> but may also be expressed as <p class=".+?">

• The ESR regex is, of course, the ending tag </p>, which must never occurs before the next line-ending to replace

giving the functional regex S/R :

SEARCH (?-si:<p class=".+?">|(?!\A)\G)(?s-i:(?!</p>).)*?\K\R

REPLACE \x20

Test it against that text :

<a href="https://www.w3schools.com/">We strongly suggest
to visit the
w3schools.com
site</a>

<p class="mb-40px">Aceasta
este o melodie alcatuita
din patru masuri:
reluata apoi de catre instrumentul solist
cu un cintec popular.</p>

<p class="Test">A SINGLE line</p>

<h1>this is
my very
first heading
</h1>

<p class="123-456 789">This is	
a quick
text to
verify if it
replaces line-endings
by a space char in <p>
tags ONLY</p>

ONLY the <p class.............<p>, multi-lines or not, should be concerned by the replacement !

Of course, these HTML commands do not represent a legal HTML file and are just used to verify the regex S/R !

Now, the generic variants, proposed by @Robin-cruise and @hellena-crainicu, with a final look-ahead only, containing the ESR region, will not work, most of a time :-(

SEARCH (?-si:BSR|(?!\A)\G).*?\K(?-si:FR)(?=(?s-i:.*?ESR))

In our case, the functional regex S/R becomes :

SEARCH (?-si:<p class=".+?">|(?!\A)\G).*?\K\R(?=(?s-i:.*?</p>))

REPLACE \x20

But if you test it against, for instance :

<p class="Test">Several
consecutive
lines</p>

<h1>this is
my very
first heading
</h1>

<p class="Test">A SINGLE line</p>

<h2>this is
my second
heading
</h2>

It would concatenate all text till the last </p> of the file, just leaving the last <h2> tag untouched. You could say : But I did add a final question mark in order to get a lazy range of chars before </p> !

You’re right ! But remember that the regex engine tries, by all means, to get a solution. So, it matches the CRLF chars, which follow lines</p>, because the regex engine considers that the .*? lazy range of chars begins immediately after the line-ending and continues till right before the third and final </p>, so defining a correct look-ahead assertion !

Thus, testing if the ESR region is not reached at any position, till a NEXT FR match, seems the only method which works properly !

Best Regards

guy038

Reminder : Move to the very beginning of text before clicking on the Find Next or Replace All button !

another alternative of Robin’s generic, a better version, can be:

(REGION-START)+(.)+\K(FIND REGEX)(?s:(?=.*(REGION-FINAL)))

The below GENERIC regex formula can be much simple made then @guy038 made

Why should you be believed over @guy038 ?

FIND: (<p class="mb-40px">)+(.)+\K(\r\n|\r|\n)(?=.*<\/p>)

REPLACE BY: \x20

The below GENERIC regex formula can be much simple made then @guy038 made in many other of his GENERIC regex formulas:

(REGION-START)+(.)+\K(FIND REGEX)(?=.*REGION-FINAL)

Find: (?-i:<p class="mb-40px">|(?!\A)\G)(?s:(?!</p>).)*?\K(?-i:(?<=[^\r\n])\R(?=[^\r\n]))

Replace by: \x20

This is just a (by now) simple replace-but-only-between-delimiters problem; see HERE for the templatized solution.