How can i extract a string text from a file using loop while all over the file?

Question

For example i have this:

"Was? Wo war ich? Ach ja.<pa>">

I need to create a new text file that will contain only:

Was? Wo war ich? Ach ja.

And i have a big file like 43mb and i need to scan all over the file and get only the places that start with " and end with <pa>" and to get the string between this tags.

I did this code so far:

private void retrivingTestText()
        {
            w = new StreamWriter(retrivedTextFile);
            string startTag = "\"";
            string endTag = "&lt;pa&gt;";
            int startTagWidth = startTag.Length;
            int endTagWidth = endTag.Length;
            string text = "\"Was? Wo war ich? Ach ja.&lt;pa&gt;\">";

            int begin = text.IndexOf(startTag);
            int end = text.IndexOf(endTag, begin + 1);

            string result = text.Substring(begin+1, end-1);
            w.WriteLine(result);
            w.Close();


        }

But now i need to make it on a big file 43mb xml file. So in the constructor i already did StreamReader r; And string f; Then i did :

r = new StreamReader(@"D:\New folder (22)\000004aa.xml")
f = r.ReadToEnd();

Now i need to use it with the code above to extract all the strings in the big file between the startTag and endTag and not only specific text.

Second thing i need to make another function so after i make changes it will know to add back all the extractes text strings to the right places where it was before between the startTag and the endTag

Thanks.

You may want to look into regular expressions... they make this sort of thing much easier. — Cameron, Apr 24 '12 at 05:33
Is your data valid XML? Can you use an XmlReader to process the file? See http://msdn.microsoft.com/en-us/library/9d83k261.aspx — Andrew Kennan, Apr 24 '12 at 05:39

score 0 · Answer 1 · edited May 23 '17 at 11:55

0

There is a similar post on how to remove HTML tags using regular expressions. Here is the link.

And another one that you can tweak, here.

edited May 23 '17 at 11:55

Community

1
1

answered Apr 24 '12 at 05:44

Robin Maben

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score 0 · Accepted Answer · answered Apr 24 '12 at 14:15

You can go for following approach to extract the data.

string word = "\"Was? Wo war ich? Ach ja<pa>\"Jain\"Romil<pa>\"";
string[] stringSeparators = new string[] { "<pa>\"" };
string ans=String.Empty;
string[] text = word.Split(stringSeparators, StringSplitOptions.None);

foreach (string s in text)
{
    if (s.IndexOf("\"") >= 0)
    {
        ans += s.Substring(s.IndexOf("\"")+1);
    }
}
return ans;

How can i extract a string text from a file using loop while all over the file?

2 Answers2