Question

there is a String which contains some @ characters, i want to find ” @ ” in my string and remove them, but it also finds and removes these ones: “@”

int atsignPlace = str.IndexOf(" @ ");
while (atsignPlace >= 0)
{
    str = str.Remove(atsignPlace,3);
    atsignPlace = str.IndexOf(" @ ");
}

i tried this code, but it removes nothing, so it always finds first ‘@’ ,which makes it an infinite loop.

int atsignPlace = str.IndexOf(" @");
while (atsignPlace >= 0)
{
    if( atsignPlace+1 < str.Length && str[atsignPlace+1] == ' ' )
        str = str.Remove(atsignPlace,3);
    atsignPlace = str.IndexOf(" @ ");
 }

Replace method also doesn’t work correct.

str = str.Replace(" @ ", String.Empty);

maybe there is a problem with ‘@’ character.

the input string is a sql query, i am trying to remove some parameters from it.

[ i have used try-catch for exceptions ]

Answer 1

Your code works fine. Short but complete program to demonstrate:

using System;

class Test
{
    static void Main() 
    {
        string before = "xyz @ abc@123";
        string after = CustomRemove(before);
        Console.WriteLine(after); // Prints xyzabc@123
    }

    static string CustomRemove(string text)
    {
        int atSignIndex = text.IndexOf(" @ ");
        while (atSignIndex >= 0)
        {
            text = text.Remove(atSignIndex, 3);
            atSignIndex = text.IndexOf(" @ ");
        }
        return text;
    }
}

EDIT: Of course, Replace works fine too:

using System;

class Test
{
    static void Main() 
    {
        string before = "xyz @ abc@123";
        string after = before.Replace(" @ ", "");
        Console.WriteLine(after); // Prints xyzabc@123
    }
}

If you’re still seeing a problem with either of these, then the issue is in how you’re using this code, not in the code itself.

One guess: you might have non-printed characters within the ” @ ” which is preventing them from being removed. But you haven’t really given us enough information to say. A short but complete program demonstrating it not working would help…