Problem with a regexp

Terisa de morgan · 06-18-2015, 12:18 AM

Hi,

I don't know if this problem goes here, but as I use the regexp for modifying the book comments in the bulk edit metadata, I don't know any other place.

My regexp is like this:

Code:

<div><p( [^>]*)?>

The problem is that this search goes wrong if I have something like:

Code:

<div><p class="pp">

Do you see any obvious problem? I've never been very comfortable with regexp.
and I'm not able to

chaley · 06-18-2015, 03:20 PM

Quote:

Originally Posted by Terisa de morgan

Code:

<div><p( [^>]*)?>

The problem is that this search goes wrong if I have something like:

Code:

<div><p class="pp">

The ? after the parenthesis is being interpreted as a normal character because there isn't a "*" matching expression immediately in front of it (the parenthesis intervenes). I assume you are trying to make the * not greedy. That is not required because the NOT ^ character set is already not greedy, stopping at the first ">".

If for some reason you really want to make the "[^>]*" not greedy then you must put the question immediately after the star, as in "[^>]*?"

DiapDealer · 06-18-2015, 03:43 PM

I think she's trying to use the question mark to make the entire group (within the parens) optional.

@Terisa: While your regex should match (it does for me when I use it in other applications), the question mark (as well the space inside the group) is probably not necessary. The * is already 0 or more repetitions, which implies that what precedes it is "optional."

When you say "goes wrong," do you mean you want your expression to match the code example you gave, or you don't want it to match?

Something like:

Code:

<div><p([^>]*)>

Should be sufficient to match any p tag that immediately follows a div tag-- regardless if the p tag has any attributes or not.

If you're looking for something else, you'll need to clarify.

Terisa de morgan · 06-18-2015, 03:58 PM

@diapdealer, thank you, you've understood me although I haven't explained myself

Yes, I want the expression to match the example I've given, and yes, I want optional the part after the the <p, so it can be an empty p.

Now, as you and @chaley have shown me the fails in the expression, I understand I should have checked it myself more thoroughly.

Thank you very much.

DiapDealer · 06-19-2015, 02:57 PM

You're welcome!

Feel free to drop the parens entirely if you don't need to capture the p tag's attributes for any reason.

06-18-2015, 12:18 AM	#1
Terisa de morgan Grand Sorcerer Posts: 6,233 Karma: 11768331 Join Date: Jun 2009 Location: Madrid, Spain Device: Kobo Clara/Aura One/Forma,XiaoMI 5, iPad, Huawei MediaPad, YotaPhone 2	Problem with a regexp Hi, I don't know if this problem goes here, but as I use the regexp for modifying the book comments in the bulk edit metadata, I don't know any other place. My regexp is like this: Code: <div><p( [^>]*)?> The problem is that this search goes wrong if I have something like: Code: <div><p class="pp"> Do you see any obvious problem? I've never been very comfortable with regexp. and I'm not able to

06-18-2015, 03:43 PM	#3
DiapDealer Grand Sorcerer Posts: 27,549 Karma: 193191846 Join Date: Jan 2010 Device: Nexus 7, Kindle Fire HD	I think she's trying to use the question mark to make the entire group (within the parens) optional. @Terisa: While your regex should match (it does for me when I use it in other applications), the question mark (as well the space inside the group) is probably not necessary. The * is already 0 or more repetitions, which implies that what precedes it is "optional." When you say "goes wrong," do you mean you want your expression to match the code example you gave, or you don't want it to match? Something like: Code: <div><p([^>])> Should be sufficient to match any p tag that immediately follows a div tag-- regardless if the p tag has any attributes or not. If you're looking for something else, you'll need to clarify. Last edited by DiapDealer; 06-18-2015 at 03:48 PM.*

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06-18-2015, 03:58 PM	#4
Terisa de morgan Grand Sorcerer Posts: 6,233 Karma: 11768331 Join Date: Jun 2009 Location: Madrid, Spain Device: Kobo Clara/Aura One/Forma,XiaoMI 5, iPad, Huawei MediaPad, YotaPhone 2	@diapdealer, thank you, you've understood me although I haven't explained myself Yes, I want the expression to match the example I've given, and yes, I want optional the part after the the <p, so it can be an empty p. Now, as you and @chaley have shown me the fails in the expression, I understand I should have checked it myself more thoroughly. Thank you very much.

06-19-2015, 02:57 PM	#5
DiapDealer Grand Sorcerer Posts: 27,549 Karma: 193191846 Join Date: Jan 2010 Device: Nexus 7, Kindle Fire HD	You're welcome! Feel free to drop the parens entirely if you don't need to capture the p tag's attributes for any reason.