Get string between delimiters from file in C#

Question

Maybe the question is familiar but I need an explanation in this case.

Let's assume that I have a file called test.txt. It has the following content:

An example of this line. The line has more than 20 characters.
[sql]SELECT * FROM LINE WHERE aLine = '123'[/sql]
blah blah blah blah...

OR what's about

An example of this line. The line has more than 20 characters.
[sql]SELECT * FROM 
       LINE 
     WHERE aLine = '123'[/sql]
blah blah blah blah...

[sql] SELECT * FROM ME[/sql]

 etc..er
[sql]
   SELECT * FROM ALL
 [/sql]

I want to get a string between [sql] and [/sql] delimiters.

How to do that ? With Regular expression ?

Thanks for patience ...

**Did you try** starting with a simple IndexOf/Substring pair? Then you can move to something less naive (regex?) in case you need. — Adriano Repetti, Jul 03 '12 at 14:20
well.. there are a lot of ways. You can find parser libraries on the net for complex things... In your case, if you have only a single tag, you could use IndexOf("[sql]"), IndexOf("[/sql]") and subString — Kek, Jul 03 '12 at 14:21

score 2 · Accepted Answer · edited May 23 '17 at 12:27

You can use the same solution found in this answer

string ExtractString(string s, string tag) {
     // You should check for errors in real-world code, omitted for brevity
     var startTag = "[" + tag + "]";
     int startIndex = s.IndexOf(startTag) + startTag.Length;
     int endIndex = s.IndexOf("[/" + tag + "]", startIndex);
     return s.Substring(startIndex, endIndex - startIndex);
}

score 1 · Answer 2 · answered Jul 03 '12 at 14:19

1

int start = foo.IndexOf("[sql]") + 5;

var sql = foo.SubString(start, foo.IndexOf("[/sql]") - start - 5);

answered Jul 03 '12 at 14:19

Alex

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you need to remove the -5 at the end. – Eren Ersönmez Jul 03 '12 at 14:25
can you see my updated question ? after `OR what's about` text – Snake Eyes Jul 08 '12 at 11:13

score 0 · Answer 3 · answered Jul 03 '12 at 14:22

0

If there is only one occurance, you can use common string operators:

string str = File.ReadAllText(@"c:\test.txt");

int start = str.IndexOf("[sql]");
int end = str.IndexOf("[/sql]");
string sql = str.Substring(start + 5, end - start - 5);

answered Jul 03 '12 at 14:22

Guffa

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1,005

score 0 · Answer 4 · answered Sep 11 '17 at 14:46

An old question but this often pops up on a Google query about searching for delimited strings. I found a good solution in

Regex: C# extract text within double quotes

in "Bart's" answer.

It's a Linq-based solution. You split the string using your delimiter character as the split character. Then you keep all the odd-numbered entries.

var stringArray = str.Split('"').Where((item, index) => index % 2 != 0);

In my case I was looking for strings delimited by a dollar sign, '$'. Example: $WantThisString$. Worked like a champ. Thanks Bart!

Get string between delimiters from file in C#

4 Answers4