asked on

searching string from a text file?

Hi,

I am trying find a string (it will be an URI) from a text file containing lines of URIs.
basically each line has an URI.

I was trying to use this Regex method but I am getting the unescape character problem.
readFile = new System.IO.StreamReader("StatusLog.txt");
string allRead = readFile.ReadToEnd();
readFile.Close();

//If the match is found in allRead

if (Regex.IsMatch(allRead, fileName)
{
return true;
}
else
{
return false;
}

Is there a way to fix this problem?
I am looking at the Regex.Escape() but not sure how to use it.

Is there another way I can search the string?
Should I do while loop and readline(), then compare?
Can't think a better way to do this?

Carlos Villegas

Hello, have you tried:

if (allRead.IndexOf(fileName, StringComparison.InvariantCultureIgnoreCase) >= 0)
{
    return true;
}
else
{               
    return false;
}

Open in new window

kaufmed

I agree with the above--I think a simple string search would be better for this purpose than would a regex. Unless you have some variance in your filenames, I can can't see any benefit to your using a regex.

I am looking at the Regex.Escape() but not sure how to use it.

Regex.Escape just parses the string you give it and escapes (i.e. adds a leading backslash to) any characters which have special meaning in regex-land. The return value of that function is the escaped string.

Should I do while loop and readline(), then compare?

If you have a really big file, then ReadLine would probably be more preferable; if your files are small, then ReadAll should be adequate.

dkim18

ASKER

if (allRead.IndexOf(fileName, StringComparison.InvariantCultureIgnoreCase) >= 0)
{
return true;
}
else
{
return false;
}

My file has these:
http://mysite.com/website1/
http://mysite.com/website2/
http://mysite.com/website2/subfolers/
http://mysite.com/website2/subfolers2/

if I was looking for http://mysite.com/website2/
Would not the indexOf() bring back three result?
I need to exact match and bring back one result from above?

I

dkim18

ASKER

readFile = new System.IO.StreamReader("StatusLog.txt");
string allRead = readFile.ReadToEnd();
readFile.Close();

//If the match is found in allRead

if (Regex.IsMatch(allRead, fileName)
{
return true;
}
else
{
return false;
}

readFile = new System.IO.StreamReader("StatusLog.txt");
            
          while ((line = readFile.ReadLine()) != null){
              
               if (line ==filename)
              {   return true; break;
               }
             }
             return fase;


something like this?

Open in new window

SOLUTION

Carlos Villegas

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ASKER CERTIFIED SOLUTION

kaufmed

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

kaufmed

Hmmm... I thought I had a space in my "whitespace" list. In case EE stripped it out, the whitespace variable should have a space in that list. I'll try again:

string whitespace = " \n\r\t";

Open in new window

dkim18

ASKER

Sorry, how do you convert char to sring here?

!whitespace.Contains(input[current]))

kaufmed

Sorry, how do you convert char to sring here?

Ah. I had Linq enabled, so I got a few extension methods! You can call the ToString method:

...!whitespace.Contains(input[current].ToString()))

Open in new window

dkim18

ASKER

never mind.
!whitespace.Contains(allRead[current].ToString()))

kaufmed

You could also change that line to:

while (current < input.Length && whitespace.IndexOf(input[current]) < 0)

Open in new window

dkim18

ASKER

Thanks guys.