Regex Matchcollection groups

Question

I already tried two days to solve the Problem, that I have a MatchCollection. In the patter is a Group and I want to have a list with the Solutions of the Group (there were two or more Solutions).

string input = "<tr><td>Mi, 09.09.15</td><td>1</td><td>PK</td><td>E</td><td>123</td><td></td></tr><tr><td>Mi, 09.09.15</td><td>2</td><td>ER</td><td>ER</td><td>234</td><td></td></tr>";
string Patter2 = "^<tr>$?<td>$?[D-M][i-r],[' '][0-3][1-9].[0-1][1-9].[0-9][0-9]$?</td>$?<td>$?([1-9][0-2]?)$?</td>$?";
Regex r2 = new Regex(Patter2);
MatchCollection mc2 = r2.Matches(input);

foreach (Match match in mc2)
{
     GroupCollection groups = match.Groups;
     string s = groups[1].Value;
     Datum2.Text = s;
}

But only the last match (2) appears in the TextBox "Datum2". I know that I have to use e.g. a listbox, but the Groups[1].Value is a string...

Thanks for your help and time. Dieter

you are replacing the Datum2 text field with s. It is not appending anything to Datum2.Text. If you want to see all matches you can say Datum2.Text = s + Datum2.Text — lazy, Sep 28 '15 at 14:36
Did you consider using other tools than regex for parsing out data from HTML strings? Did you hear about HtmlAgilityPack? — Wiktor Stribiżew, Sep 28 '15 at 14:57
There is loop there around match collection. If you want to print all matches in the text box either convert the [match collection to string array](http://stackoverflow.com/questions/11416191/how-to-convert-matchcollection-to-string-array) or use Datum2.Text = s + Datum2.Text — lazy, Sep 28 '15 at 15:04

Mariano · Accepted Answer · 2015-09-28T22:06:27.650

First thing you need to correct in the code is Datum2.Text = s; would overwrite the text in Datum2 if it were more than one match.

Now, about your regex,

^ forces a match at the begging of the line, so there is really only 1 match. If you remove it, it'll match twice.
I can't seem to understand what was intended with $? all over the pattern (just take them out).
[' '] matches "either a quote, a space or a quote (no need to repeat characters in a character class.
All dots in [0-3][1-9].[0-1][1-9].[0-9][0-9] need to be escaped. A dot matches any character otherwise.
[0-1][1-9] matches all months except "10". The second character shoud be [0-9] (or \d).

Code:

string input = "<tr><td>Mi, 09.09.15</td><td>1</td><td>PK</td><td>E</td><td>123</td><td></td></tr><tr><td>Mi, 09.09.15</td><td>2</td><td>ER</td><td>ER</td><td>234</td><td></td></tr>";
string Patter2 = "<tr><td>[D-M][i-r],[' ][0-3][0-9]\\.[0-1][0-9]\\.[0-9][0-9]</td><td>([1-9][0-2]?)</td>";
Regex r2 = new Regex(Patter2);
MatchCollection mc2 = r2.Matches(input);
string s= "";

foreach (Match match in mc2)
{
     GroupCollection groups = match.Groups;
     s = s + " " + groups[1].Value;
}

Datum2.Text = s;

Output:

1 2

DEMO

You should know that regex is not the tool to parse HTML. It'll work for simple cases, but for real cases do consider using HTML Agility Pack

Regex Matchcollection groups

1 Answers1