CODEWITHSUNDEEP
c#substring
Seabody
Seabody

Reputation: 1217

In file, if line contains substring, get all of the line from the right

I have a file. Each line looks like the following:

[00000] 0xD176234F81150469: foo

What I am attempting to do is, if a line contains a certain substring, I want to extract everything on the right of the substring found. For instance, if I were searching for 0xD176234F81150469: in the above line, it would return foo. Each string is of variable length. I am using C#.

As a note, every line in the file looks like the above, having a base-16 number enclosed in square brackets on the left, followed by a hexadecimal hash and a semicolon, and an english string afterwards.

How could I go about this?

Edit

Here is my code:

    private void button1_Click(object sender, EventArgs e)
    {
        Form1 box = new Form1();
        if(MessageBox.Show("This process may take a little while as we loop through all the books.", "Confirm?", MessageBoxButtons.YesNo, MessageBoxIcon.Information) == DialogResult.Yes)
        {
            XDocument doc = XDocument.Load(@"C:\Users\****\Desktop\books.xml");

            var Titles = doc.Descendants("Title");

            List<string> list = new List<string>();

            foreach(var Title in Titles)
            {
                string searchstr = Title.Parent.Name.ToString();
                string val = Title.Value;
                string has = @"Gameplay/Excel/Books/" + searchstr + @":" + val;
                ulong hash = FNV64.GetHash(has);
                var hash2 = string.Format("0x{0:X}", hash);

                list.Add(val + " (" + hash2 + ")");
                // Sample output: "foo (0xD176234F81150469)"
            }

            string[] books = list.ToArray();

            File.WriteAllLines(@"C:\Users\****\Desktop\books.txt", books);
        }
        else
        {
            MessageBox.Show("Aborted.", "Aborted");
        }
    }

I also iterated through every line of the file, adding it to a list<>. I must've accidentally deleted this when trying the suggestions. Also, I am very new to C#. The main thing I am getting stumped on is the matching.

Upvotes: 4

Views: 2295

Answers (4)

Seabody
Seabody

Reputation: 1217

Unfortunately, none of the other solutions worked for me. I was iterating through the hashes using foreach, so I would be iterating through all the items millions of times needlessly. In the end, I did this:

            using (StreamReader r = new StreamReader(@"C:\Users\****\Desktop\strings.txt"))
            {
                string line;
                while ((line = r.ReadLine()) != null)
                {
                    lines++;
                    if (lines >= 6)
                    {
                        string[] bits = line.Split(':');

                        if(string.IsNullOrWhiteSpace(line))
                        {
                            continue;
                        }

                        try
                        {
                            strlist.Add(bits[0].Substring(10), bits[1]);
                        }
                        catch (Exception)
                        {
                            continue;
                        }
                    }
                }
            }

            foreach(var Title in Titles)
            {
                string searchstr = Title.Parent.Name.ToString();
                string val = Title.Value;
                string has = @"Gameplay/Excel/Books/" + searchstr + ":" + val;
                ulong hash = FNV64.GetHash(has);
                var hash2 = " " + string.Format("0x{0:X}", hash);

                try
                {
                    if (strlist.ContainsKey(hash2))
                    {
                        list.Add(strlist[hash2]);
                    }
                }
                catch (ArgumentOutOfRangeException)
                {
                    continue;
                }
            }

This gave me the output I expected in a short period of time.

Upvotes: 0

Hjalmar Z
Hjalmar Z

Reputation: 1601

This works if you don't want to use Linq query.

//"I also iterated through every line of the file, adding it to a list<>." Do this again.
List<string> li = new List<string>()

//However you create this string make sure you include the ":" at the end.
string searchStr = "0xD176234F81150469:"; 

private void button1_Click(object sender, EventArgs e)
{
    foreach (string line in li)
    {
        string[] words;
        words = line.Split(' '); //{"[00000]", "0xD176234F81150469:", "foo"}

        if (temp[1] == searchStr)
        {
            list.Add(temp[2] + " (" + temp[1] + ")");
            // Sample output: "foo (0xD176234F81150469)"
        }
    }
}

Upvotes: 1

Tim Schmelter
Tim Schmelter

Reputation: 460228

You could use File.ReadLines and this Linq query:

string search = "0xD176234F81150469:";
IEnumerable<String> lines = File.ReadLines(path)
    .Select(l => new { Line = l, Index = l.IndexOf(search) })
    .Where(x => x.Index > -1)
    .Select(x => x.Line.Substring(x.Index + search.Length));

foreach (var line in lines)
    Console.WriteLine("Line: " + line);

Upvotes: 4

Ahmed KRAIEM
Ahmed KRAIEM

Reputation: 10427

string file = ...
string search= ...
var result = File.ReadLines(file)
              .Where(line => line.Contains(search))
              .Select(line => line.Substring(
                                   line.IndexOf(search) + search.Length + 1);

Upvotes: 0

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