Question

I have two strings

string str1 = "Hello World !"; // the position of W character is 6
string str2 = "peace";
//...
string result = "Hello peace !"; // str2 is written to str1 from position 6

Is there a function like this:

string result = str1.Rewrite(str2, 6); // (string, position)

EDITED
This “Hello World !” is just an example, I don’t know whether there is “W” character in this string, what I only know are: str1, str2, position (int)

Answer 1

@danludwigs answer is better from a code understandability perspective, however this version is a tad faster. Your explanation that you are dealing with binary data in string format (wtf bbq btw 🙂 ) does mean that speed might be of the essence. Although using a byte array or something might be better than using a string 🙂

public static string RewriteChar(this string input, string replacement, int index)
{
  // Get the array implementation
  var chars = input.ToCharArray();
  // Copy the replacement into the new array at given index
  // TODO take care of the case of to long string?
  replacement.ToCharArray().CopyTo(chars, index);
  // Wrap the array in a string represenation
  return new string(chars);
}