Replacing a substring at a specific position

[paarfal]

Hi all, need some help.

I want to replace the second character in a string, regardless of what character that is.

If I try the replace the second character with the (substring 1, 1) all instances of that character gets replaced.
I just want to replace the one sitting at position 2 in the string.

Ex Good -> Gxod, not Gxxd

Thanks in advance

Patrik

[kmoorman]

paarfal,

One option is to use the classic BASIC MID statement:

Dim myString As String = "abcde"

Mid(myString, 2, 1) = "x"

MsgBox(myString)

(Of course, now the .Net purists will respond that you should not use the MID statement.)

Kerry Moorman

[Phil Weber]

In VB, you can use the Mid statement:

Mid(theString, 2, 1) = "x"

There's no equivalent in C#. You could add a reference to the Microsoft.VisualBasic namespace and call the Mid statement from C#, or you could convert the string to an array of characters, update the desired character, then create a new string from the char array.

[David Anton]

In VB, you could have (add semi-colon for C#)
myString = myString.Remove(1, 1).Insert(1, "x")

Of course, not quite as direct as the Mid statement.

[jain25rajesh]

in C# you can use in this way
TextBox2.Text =TextBox1.Text.Replace(TextBox1.Text.Substring(1,1),"p");

here p is the newly replaced char.

[Phil Weber]

Raj: I'm pretty sure that will replace all occurrences of the second character with the letter 'p'. So, "good" would become "gppd".

[paarfal]

Hi all,

Thaks for your suggestions. I'll try work it out based on them.

Regards,

Patrik

[aldus]

I think the best in C# would be:
TextBox2.Text =TextBox1.Text.Remove(1,1).Insert(1,"p");
cheers

[dsalmon]

Why couldn't you just use ...
newstring = LEFT(oldstring, 1) & newcharacter & MID(oldstring, 3)

[Phil Weber]

That would work, but it's less efficient than Mid(theString, 2, 1) = "x" due to its use of concatenation.

[dsalmon]

Absolutely, but it is simpler to understand for new programmers. And the performance hit is only noticable if the number of iterations on it are extremely large.

[Phil Weber]

OK, how about this:

' Replace second character of theString with 'x'
Mid(theString, 2, 1) = "x"

That's efficient and easy for new programmers to understand (and it doesn't teach them bad habits ;-).

[dsalmon]

Works for me! Personally I have always used MID() = X in the manner you describe. Although I wouldn't call the concatenation a "bad habit" ... just not the most efficient one.

[jannesc]

A bit of filthy wat to do it, but it works.

string editString = "Good";

StringBuilder sb = new StringBuilder(editString);
sb.Remove(1, 1);
sb.Insert(1, "x");

editString = sb.ToString();