StringBuilder search with indexOf and lastIndexOf

In this chapter you will learn:

How to search a string inside a StringBuilder
How to search a StringBuilder from the end

Search a string inside a StringBuilder

We can search a StringBuilder with the following two methods.

int indexOf(String str)
Returns the index of the first occurrence of the specified substring.
int indexOf(String str, int fromIndex)
Returns the index of the first occurrence of the specified substring, starting at the specified index.

public class Main {
  public static void main(String[] argv) {
    StringBuilder sb = new StringBuilder();
    sb.append("java2s.com");
    //  ja  va 2  s .c o m
    int index = sb.indexOf("com");
    
    System.out.println(index);

  }
}

The output:

Search a StringBuilder from the end

The following two methods search a substring within StringBuilder from the end.

int lastIndexOf(String str)
returns the index of the rightmost occurrence of the specified substring.
int lastIndexOf(String str, int fromIndex)
returns the index of the last occurrence of the specified substring.

public class Main {
/*jav a 2  s .  c om*/
  public static void main(String[] arg) {
    StringBuilder phrase = new StringBuilder("one two three four");
    int position = phrase.lastIndexOf("three");

    System.out.println(position);
  }

}