如何解析读取所有行的文本文件中的特定字符串？

Question

In each line i want to parse the string after the tag

I know it's html but i copied this part of the html to text file. For example the first two lines in the text file are like this:

 <li>602 — <a href="/w/index.php?title=Text602&amp;action=edit&amp;redlink=1" class="new" title="Text602 (page does not exist)">Text602</a> document</li> <li>ABW — <a href="/wiki/AbiWord" title="AbiWord">AbiWord</a> Document</li> 

I want to parse the 602 from the first line and the ABW from the second line. What i tried to do is:

 private void ParseFilesTypes() { string[] lines = File.ReadAllLines(@"E:\\New folder (44)\\New Text Document.txt"); foreach (string str in lines) { int r = str.IndexOf("<li>"); if (r >= 0) { int i = str.IndexOf(" -", r + 1); if (i >= 0) { int c = str.IndexOf(" -", i + 1); if (c >= 0) { i++; MessageBox.Show(str.Substring(i, c - i)); } } } } } 

But c is all the time -1

Answer 1

I think it is a case when regex would be useful (unless there will be no li attributes):

var regex = new Regex("^<li>(.+) —");
foreach (string str in lines)
{
     var m = regex.Match(str);
     if (m.Success)
        MessageBox.Show(m.Groups[1].Value);
}

Answer 2

Actually, your problem is that you're reading the file with the incorrect encoding . You have a special character in your file — and not - . So you need to correct this character in your code and read the file in the correct encoding. If you debug your string read with wrong encoding, you'll see a black diamond instead of — .

Also, you need to remove the space before — or replace i + 1 with i ;

private static void ParseFilesTypes()
{
    string sampleFilePath = @"log.txt";
    string[] lines = File.ReadAllLines(@"log.txt", Encoding.GetEncoding("windows-1252"));
    foreach (string str in lines)
    {
        int r = str.IndexOf("<li>");
        if (r >= 0)
        {
            int i = str.IndexOf(" —", r + 1);
            if (i >= 0)
            {

                int c = str.IndexOf(" —", i);
                if (c >= 0)
                {
                    i++;
                    int startIndex = r + "<li>".Length;
                    int length = i - startIndex - 1;
                    string result = str.Substring(r + "<li>".Length, length);
                    MessageBox.Show(result);
                }
            }
        }
    }
}