How to trim the illegal characters from a string

Question

I will read a file from my computer using

   StreamReader sr = new StreamReader(FileName);

            string str = sr.ReadToEnd();

In this i am getting some illegal characters like /n,/r and some other.

I Would like to replace illegal characters with a empty character. I tried of making an character array but i did not able to remove those so can any one help me

Answer 1

You can use the String.Replace method:

string str = sr.ReadToEnd().Replace("\r", "").Replace("\n", "");

However it's not a very good idea if the string is long and you have a long list of illegal characters, because each call to Replace will create a new instance of String. A better option would be to filter out the illegal characters using Linq :

char[] illegalChars = new[] { '\r', '\n' }; // add other illegal chars if needed
char[] chars = sr.ReadToEnd().Where(c => !illegalChars.Contains(c)).ToArray();
string str = new String(chars);

However the call to Contains adds overhead, it is faster to test directly against each illegal character:

char[] chars = sr.ReadToEnd().Where(c => c != '\r' && c != '\n').ToArray();
string str = new String(chars);

And for completeness, here's an even faster version:

StringBuilder sb = new StringBuilder();
foreach(char c in sr.ReadToEnd())
{
    if (c != '\r' && c != '\n')
        sb.Append(c);
}
string str = sb.ToString();

Answer 2

StreamReader sr = new StreamReader (FileName);

StringBuilder sb = new StringBuilder (sr.ReadToEnd());

sb.Replace ("\r\n", String.Empty);
sb.Replace ("\n", String.Empty);

string hereIsYourString = sb.ToString ();

Answer 3

string str = string.Join(string.Empty, File.ReadAllLines(FileName));