BeginnersBook

Java StringBuffer delete()

By Chaitanya Singh | Filed Under: java

Java StringBuffer delete() method is used to delete a part of the string. A StringBuffer instance represents a character sequence. We can delete a portion of this char sequence, by specifying start and end index in delete() method.

Syntax of delete() method

//deletes a substring from first char till 5th char
sb.delete(0, 5); //end index is exclusive

//deletes a substring from 2nd char till 4th char
sb.delete(1, 4);

Here, sb is an object of StringBuffer class.

delete() Description

public StringBuffer delete(int start, int end): It deletes a substring from this StringBuffer instance from start index till end index.

This method throws StringOutOfBoundsException, if any of the following condition occurs:

  • If indexes are negative.
  • If any of the index is greater than or equal to the length.
  • if start index > end index.

delete() Parameters

The delete() method of Java StringBuffer class takes a two parameters:

  • start: It represents the starting index, deletion starts from here. It is inclusive.
  • end: It represents the end index, deletion end here. It is exclusive.

delete() Return Value

  • It returns a new StringBuffer object containing the resultant string (char sequence ) after deletion.

Example 1: Deleting a substring

public class JavaExample {
  public static void main(String[] args) {
    StringBuffer sb = new StringBuffer("BeginnersBook.com");
    System.out.println("String: "+sb);

    //deleting the substring "Book.com"
    sb = sb.delete(9, sb.length());
    System.out.println("String after deletion: "+sb);
  }
}

Output:

Java StringBuffer delete() Output 1

Example 2: If start and end Indexes are same

public class JavaExample {
  public static void main(String[] args) {
    StringBuffer sb = new StringBuffer("Welcome");
    System.out.println("String: "+sb);

    //start and end index are equal
    //nothing will happen as start index is inclusive and
    //end index is exclusive
    sb = sb.delete(2, 2);
    System.out.println("String after deletion: "+sb);
  }
}

Output:

Java StringBuffer delete() Output 2

Example 3: Removing first and last character

public class JavaExample {
  public static void main(String[] args) {
    StringBuffer sb = new StringBuffer("Sample");
    System.out.println("String: "+sb);

    //removing first character
    sb = sb.delete(0, 1);

    //removing last character
    sb = sb.delete(sb.length()-1, sb.length());

    System.out.println("String after deletion: "+sb);
  }
}

Output:

Java StringBuffer delete() Output 3

Example 4: Removing last two characters

public class JavaExample {
  public static void main(String[] args) {
    StringBuffer sb = new StringBuffer("Sample");
    System.out.println("String: "+sb);

    //removing last two character character
    sb = sb.delete(sb.length()-1, sb.length());
    sb = sb.delete(sb.length()-1, sb.length());

    System.out.println("String after deletion: "+sb);
  }
}

Output:

Java StringBuffer delete() Output 4

Example 5: If start index is greater than the end index

public class JavaExample {
  public static void main(String[] args) {
    StringBuffer sb = new StringBuffer("Welcome");
    System.out.println("String: "+sb);
    //start index is greater than end index
    sb = sb.delete(2, 1);
    System.out.println("String after deletion: "+sb);
  }
}

Output:

Java StringBuffer delete() Output 5
❮ Java StringBuffer