extract information from xml using regular expression

Question

I need extract the author from the text using regex. Also, I need have the index of every tags and authors. I tried few parser, none of them can preserve the index correctly. So the only solution is using regex. I have following regex and it has a problem on "[^]" How could I fix this regex:

<post\\s*author=\"([^\"]+)\"[^>]+>[^</post>]*</post>

in order to extract the author in following text:

<post author="luckylindyslocale" datetime="2012-03-03T04:52:00" id="p7">
<img src="http://img.photobucket.com/albums/v303/lucky196/siggies/ls1.png"/>

Grams thank you, for this wonderful tag and starting this thread. I needed something to encourage me to start making some new tags.

<img src="http://img.photobucket.com/albums/v303/lucky196/holidays/stpatlucky.jpg"/>
Cruelty is one fashion statement we can all do without. ~Rue McClanahan
</post>

[Regex is not best tool to parse HTML](http://stackoverflow.com/a/1732454/1393766). XML or HTML parser is. Also which language is this question about Java or JavaScript? In Java you shouldn't surround regex with `/`. — Pshemo, Aug 05 '14 at 15:43
@Pshemo Yes, you are right and I don't know how to fix that. / works in java. — user2372074, Aug 05 '14 at 15:52

Sotirios Delimanolis · Accepted Answer · 2014-08-05T16:06:23.220

1

Why couldn't regex:
<post\\s*author=\"([^\"]+)\"[^>]+>[^</post>]*</post>
extract the author in following text.

Because

[^</post>]*

represents a character class and will match everything but the characters <, /, p, o, s, t, and > 0 or more times.

That doesn't happen in your text. As for how to fix it, consider using the following regex

<post\s*author=\"([^\"]+?)\"[^>]+>(.|\s)*?<\/post>
// obviously, escape appropriate characters in Java String literals

with a multiline flag.

edited Aug 05 '14 at 16:06

answered Aug 05 '14 at 15:53

Sotirios Delimanolis

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Yes, I actually aware the problem. But I couldn't fix it. – user2372074 Aug 05 '14 at 15:58
@user2372074 You should probably change your question then. – Sotirios Delimanolis Aug 05 '14 at 15:59
Thanks. Two question: 1. Is (.|\s)*? equivalent as .*? 2. is (.|\s) also include the ? Thanks – user2372074 Aug 05 '14 at 16:46
@user2372074 1. So `.` doesn't match new line characters, so you need `\s` for whitespace (or make it more specific and find the pattern for a new line). 2. No, it shouldn't because of the `?` that follows `(.|\s)`. – Sotirios Delimanolis Aug 05 '14 at 17:07

score 0 · Answer 2 · edited May 23 '17 at 11:57

0

You can just do it like the following

/<post author="(.*?)"/

Working Demo

The comments are correct though with Regex not being the best tool to parse HTML. But this should do what you are looking for

edited May 23 '17 at 11:57

Community

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answered Aug 05 '14 at 15:47

Halfwarr

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Do you understand my question? Do you know any parser can preseve the offset? Most people know regex is not best tool to parse XML or HTML, so don't repeat that. BTW, you solution is very unsafe by any means. – user2372074 Aug 05 '14 at 15:51
@user2372074 How exactly is it unsafe? What are you trying to do? Also, no I have no idea what you mean by offset. – Halfwarr Aug 05 '14 at 15:53
offset means I need have the index of author from beginning of the text. – user2372074 Aug 05 '14 at 15:56
1

@user2372074 write a parser that preserves offsets. Then you'll have a parser that preserves offsets. – David Conrad Aug 05 '14 at 16:42
@David I would if I have time. Writing a parser seems not trivial, although I never tried. – user2372074 Aug 05 '14 at 16:47

extract information from xml using regular expression

2 Answers2