StringBuilder deleteCharAt() in Java with Examples

The deleteCharAt(int index) method of StringBuilder class remove the character at the given index from String contained by StringBuilder. This method takes index as a parameter which represents the index of char we want to remove and returns the remaining String as StringBuilder Object. This StringBuilder is shortened by one char after application of this method. Syntax:

public StringBuilder deleteCharAt(int index)

Parameters: This method accepts one parameter index represents index of the character you want to remove. Return Value: This method returns this StringBuilder object after removing the character. Exception: This method throws StringIndexOutOfBoundsException if the index is less than zero, or index is larger than the length of String. Below programs demonstrate the deleteCharAt() method of StringBuilder Class: Example 1:

Java

// Java program to demonstrate
// the deleteCharAt() Method.

class GFG {
    public static void main(String[] args)
    {

        // create a StringBuilder object
        // with a String pass as parameter
        StringBuilder
            str
            = new StringBuilder("WelcomeGeeks");

        // print string
        System.out.println("Before removal String = "
                           + str.toString());

        // remove the Character from index 8
        StringBuilder afterRemoval = str.deleteCharAt(8);

        // print string after removal of Character
        System.out.println("After removal of character"
                           + " at index 8 = "
                           + afterRemoval.toString());
    }
}

Output:

Before removal String = WelcomeGeeks
After removal of character at index 8 = WelcomeGeks

Example 2:

Java

// Java program to demonstrate
// the deleteCharAt() Method.

class GFG {
    public static void main(String[] args)
    {

        // create a StringBuilder object
        // with a String pass as parameter
        StringBuilder
            str
            = new StringBuilder("GeeksforGeeks");

        // print string
        System.out.println("Before removal String = "
                           + str.toString());

        // remove the Character from index 3
        str = str.deleteCharAt(3);

        // print string after removal of Character
        System.out.println("After removal of Character"
                           + " from index=3"
                           + " String becomes => "
                           + str.toString());

        // remove the substring from index 5
        str = str.deleteCharAt(5);

        // print string after removal of Character
        System.out.println("After removal of Character"
                           + " from index=5"
                           + " String becomes => "
                           + str.toString());
    }
}

Output:

Before removal String = GeeksforGeeks
After removal of Character from index=3 String becomes => GeesforGeeks
After removal of Character from index=5 String becomes => GeesfrGeeks

Example 3: To demonstrate IndexOutOfBoundException 

Java

// Java program to demonstrate
// exception thrown by the deleteCharAt() Method.

class GFG {
    public static void main(String[] args)
    {

        // create a StringBuilder object
        // with a String pass as parameter
        StringBuilder
            str
            = new StringBuilder("evil dead_01");

        try {

            // make index > length of String
            StringBuilder
                afterRemoval
                = str.deleteCharAt(14);
        }

        catch (Exception e) {
            System.out.println("Exception: " + e);
        }
    }
}

Output:

Exception: java.lang.StringIndexOutOfBoundsException: String index out of range: 14

Reference: https://docs.oracle.com/javase/10/docs/api/java/lang/StringBuilder.html#deleteCharAt(int)