replacing string using extension method

Question

If I have string and I want to replace last character from that string with star for example.

I tried this

var myString = "ABCDEFGH";
myString.ReplaceCharacter(mystring.Length - 1, 1, "*"); 

public static string ReplaceCharacter(this string str, int start, int length, string replaceWith_expression)
{
    return str.Remove(start, length).Insert(start, replaceWith_expression);
}

I tried to use this extension method but this doesn't work. Why this doesn't work?

possible duplicate of [C# string replace does not work](http://stackoverflow.com/questions/13277667/c-sharp-string-replace-does-not-work) — Eugene Podskal, May 27 '15 at 20:12

adricadar · Answer 1 · 2015-05-27T17:33:59.053

8

The method, as it is, replace the character, but you have to catch the result

myString = myString.ReplaceCharacter(myString.Length - 1, 1, "*");

edited May 27 '15 at 17:33

answered May 27 '15 at 17:26

adricadar

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score 2 · Answer 2 · answered May 27 '15 at 17:44

The problem is that strings are immutable. The methods replace, substring etc do not change the string itself. They create a new string and replace it. So for the above code to be correct it should be

myString = myString.ReplaceCharacter(myString.Length - 1, 1, "*");

replacing string using extension method

2 Answers2