How can I match HTML elements with regular expressions?

Question

The following codes does not work, I am trying to retrive TR strings from a HTML table. Is there any issue with this code or any other solution available?

public static List<string> GetTR(string Tr)
{
    List<string> trContents = new List<string>();

    string regexTR = @"<(tr|TR)[^<]+>((\s*?.*?)*?)<\/(tr|TR)>";

    MatchCollection tr_Matches = Regex.Matches(Tr, regexTR, RegexOptions.Singleline);
    foreach (Match match in tr_Matches)
    {
        trContents.Add(match.Value);
    }

    return trContents;
}

Sample input string is given below:

"<TR><TD noWrap align=left>abcd</TD><TD noWrap align=left>SPORT</TD><TD align=left>5AT</TD></TR>"

Required reading: http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454 - or in summary: **don't use regex to parse HTML** — Marc Gravell, Jan 28 '11 at 15:23

score 6 · Accepted Answer · edited Nov 24 '17 at 22:37

6

Parsing HTML with regular expressions is asking for trouble.

Do the job properly using something like HTML Agility Pack.

edited Nov 24 '17 at 22:37

carla

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answered Jan 28 '11 at 15:21

LukeH

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"Parsing HTML with regular expressions is asking for trouble." seems to become a regular expression here.... – Caspar Kleijne Jan 28 '11 at 15:23
but its true ... since HTML is not necessarily regular – Hannes Jan 28 '11 at 15:27
overwhelmed by the swift response, thank you LukeH & ChosPandion. let me try the HTML Agility Pack. – Kannan Jan 28 '11 at 15:32

score 0 · Answer 2 · answered Jan 28 '11 at 15:25

0

I think this regular expression would be more appropriate:

<(tr|TR)[^>]*>.*<\/\1>

answered Jan 28 '11 at 15:25

ChaosPandion

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score 0 · Answer 3 · answered Jan 28 '11 at 15:28

this regex matches your input string:

<(tr|TR)+>((\s*?.*?)*?)<\/(tr|TR)>

i removed "[^<]"... not sure why you need that. also, try to add a non-greedy match...

however, it is better to go with something like HTML Agility Pak (if you want to keep your sanity) :)

score 0 · Answer 4 · edited Jan 28 '11 at 15:38

0

(<(tr|TR)[^<]*>)(.+)((<\(tr|TR)[^<]*>)

edited Jan 28 '11 at 15:38

R. Martinho Fernandes

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answered Jan 28 '11 at 15:29

Senad Meškin

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How can I match HTML elements with regular expressions?

4 Answers4