String

Java String lastIndexOf Example

As we disscused in a previous post about Java String indexOf() Example, many times we need to search for a character set in a Java String. Thus we need a “tool”, a method that will help us make it.

So, in this example we are going to talk about identifying characters and subsequences of characters through Java Strings, with the method lastIndexOf().

String static lastIndexOf() method:

The lastIndexOf()(String or character target) method searches right-to-left inside the given string for a “target” string. The method returns the index number where the target string is last found or -1 if the target is not found. Like equals(), the lastIndexOf() method is case-sensitive, so uppercase and lowercase chars are considered to be different. The count of the index number starts from left to right though.

  • int lastIndexOf(String str): Returns the index within this string of the last occurrence of the specified substring. If it does not occur as a substring, -1 is returned.
  • int lastIndexOf()(String str, int fromIndex): Returns the index within this string of the last occurrence of the specified character, searching backwards, starting at the specified index. If it does not occur, -1 is returned.

We can use the same methods in order to find the index of the last occurrence of a specified character within the string:

  • int lastIndexOf(int ch)
  • int lastIndexOf(int ch, int fromIndex)

Example:

JavaStringLastIndexOf.java

package com.javacodegeeks.javabasics.string;

public class JavaStringLastIndexOf {

   public static void main(String args[]) {

   String str = new String("Hello JavaCodeGeeks! This is my second post.");

   String subStr1 = new String("JavaCodeGeeks");
   String subStr2 = new String("JavaGeeks");

   System.out.print("Found Index :");
   System.out.println(str.lastIndexOf('e')); //finds the last occurrence of 'e'

   System.out.print("Found Index :");
   System.out.println(str.lastIndexOf('e', 20)); //finds the last occurrence of 'e' before the 20th character

   System.out.print("Found Index :");
   System.out.println(str.lastIndexOf(subStr1)); //finds the last occurrence of "JavaCodeGeeks"

   System.out.print("Found Index :");
   System.out.println(str.lastIndexOf(subStr1, 15)); //finds the last occurrence of "JavaCodeGeeks" before the 15th character

   System.out.print("Found Index :");
   System.out.println(str.lastIndexOf(subStr2)); //finds the last occurrence of "JavaGeeks"

   }
}

Output:

Found Index :33
Found Index :16
Found Index :6
Found Index :6
Found Index :-1

This was the example of Java String lastIndexOf() method.

Chryssa Aliferi

Chryssa is a Computer Science graduate from Athens University of Economic and Business. During her studies, Chryssa carried out a great variety of projects ranging from networking to software engineering. She is very keen on front end development especially on mobile technologies and web applications. She has worked as a junior Software Engineer in the telecommunications area and currently works as an Android Developer.
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