Add, Remove, Replace String In C#

string str1 = "ppp";  
string strRes = str1.Insert(2, "bbb");  
Console.WriteLine(strRes.ToString());  

string founder = "Mahesh Chand is a founder of C# Corner";  
// Remove all characters after first 25 chars  
string first25 = founder.Remove(25);  
Console.WriteLine(first25);  

// Remove characters start at the 10th position, next 12 characters  
String newStr = founder.Remove(10, 12);  
Console.WriteLine(newStr);  

// Remove everything after founder  
int pos = founder.IndexOf("founder");  
if (pos >= 0) {  
    // String after founder  
    string afterFounder = founder.Remove(pos);  
    Console.WriteLine(afterFounder);  
    // Remove everything before founder but include founder  
    string beforeFounder = founder.Remove(0, pos);  
    Console.Write(beforeFounder);  
}  

using System;  
namespace RemoveStringSample {  
    class Program {  
        static void Main(string[] args) {  
            /** Remove sample **/  
            string founder = "Mahesh Chand is a founder of C# Corner";  
            // Remove all characters after first 25 chars  
            string first25 = founder.Remove(25);  
            Console.WriteLine(first25);  
            // Remove characters start at 10th position, next 12 characters  
            String newStr = founder.Remove(10, 12);  
            Console.WriteLine(newStr);  
            int pos = founder.IndexOf("founder");  
            if (pos >= 0) {  
                // String after founder  
                string afterFounder = founder.Remove(pos);  
                Console.WriteLine(afterFounder);  
                // Remove everything before founder but include founder  
                string beforeFounder = founder.Remove(0, pos);  
                Console.Write(beforeFounder);  
            }  
            Console.ReadKey();  
        }  
    }  
}  

Listing 1.

Replace Strings In C#

String.Replace() method replaces a character or a string with another character or string in a string.

In C#, Strings are immutable. That means the method does not replace the characters or strings from a string. The method creates and returns a new string with new characters or strings.

String.Replace() method has two overloaded forms.

Method	Description
Replace(Char, Char)	Returns a new string in which all occurrences of a specified Unicode character in this instance are replaced with another specified Unicode character.
Replace(String, String)	Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string.

Example 1

The following example replaces all commas with a colon in a string.

// Replace a char  
string odd = "1, 3, 5, 7, 9, 11, 13, 15, 17, 19";  
Console.WriteLine($ "Original odd: {odd}");  
string newOdd = odd.Replace(',', ':');  
Console.WriteLine($ "New Odd: {newOdd}");  

The following example replaces all “Beniwal” with an empty string so only first names are copied to the new string.

string authors = "Mahesh Beniwal, Neel Beniwal, Raj Beniwal, Dinesh Beniwal";  
Console.WriteLine($ "Authors with last names: {authors}");  
// Remove all Beniwal with space and remove space with empty string  
string firstNames = authors.Replace(" Beniwal", "");  
Console.WriteLine($ "Authors without last names: {firstNames}");  

The complete program is listed in Listing 1.

using System;  
namespace ReplaceStringSample {  
    class Program {  
        static void Main(string[] args) {  
            /** Replace sample **/  
            // Replace a char  
            string odd = "1, 3, 5, 7, 9, 11, 13, 15, 17, 19";  
            Console.WriteLine($ "Original odd: {odd}");  
            string newOdd = odd.Replace(',', ':');  
            Console.WriteLine($ "New Odd: {newOdd}");  
            string authors = "Mahesh Beniwal, Neel Beniwal, Raj Beniwal, Dinesh Beniwal";  
            Console.WriteLine($ "Authors with last names: {authors}");  
            // Remove all Beniwal with space and remove space with empty string  
            string firstNames = authors.Replace(" Beniwal", "");  
            Console.WriteLine($ "Authors without last names: {firstNames}");  
            Console.ReadKey();  
        }  
    }  
}  

Listing 1.

The output of Listing 1 looks like Figure 1.

Figure 1.

The Split method separates strings by a specified set of characters and places these strings into an array of strings. For example, the following source code splits strArray based on ',' and stores all separated strings in an array.

string str1 = "ppp";  
string str2 = "ccc";  
string str3 = "kkk";  
string strAll3 = str1 + ", " +str2+", "+str3 ;  
string[] strArray = strAll3.Split(',');  
foreach (string itm in strArray)  
{  
   Console.WriteLine(itm.ToString() );  
}  

The output from the above code is shown below.

Conclusion

To learn more about C# strings, check out the String In C# tutorial to learn more about strings and how to work with strings in C#.