How to continue from where I have been searching to find the index?
How to continue from where I have been searching to find the index?
I am searching in a file to find the index of a character; then I have to continue from there to find the index of the next character. For example : string is " habcdefghij"
int index = message.IndexOf("c");
开发者_StackOverflow Label2.Text = index.ToString();
label1.Text = message.Substring(index);
int indexend = message.IndexOf("h");
int indexdiff = indexend - index;
Label3.Text = message.Substring(index,indexdiff);
so it should return "cedef"
but the second search starts from the beginning of the file, it will return the index of first h rather than second h:-(
You can specify a start index when using String.IndexOf. Try
//...
int indexend = message.IndexOf("h", index);
//...
int index = message.IndexOf("c");
label1.Text = message.Substring(index);
int indexend = message.IndexOf("h", index); //change
int indexdiff = indexend - index;
Label3.Text = message.Substring(index, indexdiff);
This code finds all the matches, and shows them in order:
// Find the full path of our document
System.IO.FileInfo ExecutableFileInfo = new System.IO.FileInfo(System.Reflection.Assembly.GetEntryAssembly().Location);
string path = System.IO.Path.Combine(ExecutableFileInfo.DirectoryName, "MyTextFile.txt");
// Read the content of the file
string content = String.Empty;
using (StreamReader reader = new StreamReader(path))
{
content = reader.ReadToEnd();
}
// Find the pattern "abc"
int index = content.Length - 1;
System.Collections.ArrayList coincidences = new System.Collections.ArrayList();
while(content.Substring(0, index).Contains("abc"))
{
index = content.Substring(0, index).LastIndexOf("abc");
if ((index >= 0) && (index < content.Length - 4))
{
coincidences.Add("Found coincidence in position " + index.ToString() + ": " + content.Substring(index + 3, 2));
}
}
coincidences.Reverse();
foreach (string message in coincidences)
{
Console.WriteLine(message);
}
Console.ReadLine();
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