RegEx to replace only inside certain tags?

phossler · 03-03-2015, 06:06 PM

If there is something like

<h1>Text Text <b>Bold Text</b> Text Text</h1>

<p>Text Text <b>Bold Text</b> Text Text</p>

Q: is there a way to replace (delete) the <b> and </b> only if they are inside the h1 tags?

I got this far

Find: (<[Hh][1-6]>)(.+?)(<[biu]>)(.+?)(</\3>)(.+?)<(</[Hh][1-6]>)

Replace: \1\2\4\6\7

but it doesn't work because I can't figure out how to get the red back reference to match the blue tag

Q2: is there a better way?

eschwartz · 03-03-2015, 06:21 PM

The backreference works fine -- it just matches "(<[bui]>)"

Use "<([bui])>" instead, unless in fact you wish to match html which looks like ..."<b>some text</<b>>"...

theducks · 03-03-2015, 06:47 PM

are you supposed to escape the \3

jhowell · 03-03-2015, 06:48 PM

That RE will also match the following text:

<h1>title</h1>this has <b>bold</b> text.<h2>subtitle</h2>

eschwartz · 03-03-2015, 07:27 PM

Quote:

Originally Posted by theducks

are you supposed to escape the \3

No -- you escape the 3 by saying \3 and making it special...

Quote:

Originally Posted by jhowell

That RE will also match the following text:

<h1>title</h1>this has <b>bold</b> text.<h2>subtitle</h2>

True, which is why I prefer to search for rendered text with

Code:

[^<>]+

instead of

Code:

.+

But the main issue is capturing the right backreferences.

phossler · 03-03-2015, 08:21 PM

@eschwartz, theducks, jhowell

Thanks for the help!!

This is what I ended up with (so far) and it has of the advantage of apparently working

I don't understand yet the part in red, but I did incorporate your feedback and that made a big difference

Find: <([Hh][1-6])><([biu])>([^<>]+)(</\2>)</\1>
Replace: <\1>\3</\1>

So thanks again

eschwartz · 03-03-2015, 09:24 PM

The bit in red simply tells the regex, instead of looking for "all text", look for "all text as long as it doesn't have the < or > which signify tags".

To be really advanced, you would use a negative lookaround checking for specific tags, but at that point it might be worth moving on to some engine that can actually parse html.

03-03-2015, 06:06 PM	#1
phossler Wizard Posts: 1,092 Karma: 447222 Join Date: Jan 2009 Location: Valley Forge, PA, USA Device: Kindle Paperwhite	RegEx to replace only inside certain tags? If there is something like <h1>Text Text <b>Bold Text</b> Text Text</h1> <p>Text Text <b>Bold Text</b> Text Text</p> Q: is there a way to replace (delete) the <b> and </b> only if they are inside the h1 tags? I got this far Find: (<[Hh][1-6]>)(.+?)(<[biu]>)(.+?)(</\3>)(.+?)<(</[Hh][1-6]>) Replace: \1\2\4\6\7 but it doesn't work because I can't figure out how to get the red back reference to match the blue tag Q2: is there a better way?

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03-03-2015, 06:21 PM	#2
eschwartz Ex-Helpdesk Junkie Posts: 19,421 Karma: 85400180 Join Date: Nov 2012 Location: The Beaten Path, USA, Roundworld, This Side of Infinity Device: Kindle Touch fw5.3.7 (Wifi only)	The backreference works fine -- it just matches "(<[bui]>)" Use "<([bui])>" instead, unless in fact you wish to match html which looks like ..."<b>some text</<b>>"...

03-03-2015, 06:47 PM	#3
theducks Well trained by Cats Posts: 31,327 Karma: 62025226 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	are you supposed to escape the \3

03-03-2015, 06:48 PM	#4
jhowell Grand Sorcerer Posts: 7,171 Karma: 92500001 Join Date: Nov 2011 Location: Charlottesville, VA Device: Kindles	That RE will also match the following text: <h1>title</h1>this has <b>bold</b> text.<h2>subtitle</h2>

03-03-2015, 08:21 PM	#6
phossler Wizard Posts: 1,092 Karma: 447222 Join Date: Jan 2009 Location: Valley Forge, PA, USA Device: Kindle Paperwhite	@eschwartz, theducks, jhowell Thanks for the help!! This is what I ended up with (so far) and it has of the advantage of apparently working I don't understand yet the part in red, but I did incorporate your feedback and that made a big difference Find: <([Hh][1-6])><([biu])>([^<>]+)(</\2>)</\1> Replace: <\1>\3</\1> So thanks again

03-03-2015, 09:24 PM	#7
eschwartz Ex-Helpdesk Junkie Posts: 19,421 Karma: 85400180 Join Date: Nov 2012 Location: The Beaten Path, USA, Roundworld, This Side of Infinity Device: Kindle Touch fw5.3.7 (Wifi only)	The bit in red simply tells the regex, instead of looking for "all text", look for "all text as long as it doesn't have the < or > which signify tags". To be really advanced, you would use a negative lookaround checking for specific tags, but at that point it might be worth moving on to some engine that can actually parse html.

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