How to remove characters from a string, except those in a list

Question

This is my string value:

string str = \"32 ab d32\";

And this list is my allowed characters:

var allowedCharacters = new List&l         


        

Answer 1

Here is a simple but performant foreach solution:

Hashset lstAllowedCharacters = new Hashset{'a','b','c','2',' '};

var resultStrBuilder = new StringBuilder(srVariable.Length);

foreach (char c in srVariable) 
{
    if (lstAllowedCharacters.Contains(c))
    {
        resultStrBuilder.Append(c);
    }
    else
    {
        resultStrBuilder.Append(" ");
    }
}

srVariable = resultStrBuilder.ToString();