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Some versions of lastIndexOf() method




Methods	Description
public int lastIndexOf(char ch)	It returns the last index of the char ch found in the String object.
public int lastIndexOf(String str)	It returns the last index of the String str found in the String object.








Note :


lastIndexOf() method returns -1 if the searched char/string(passed to this method) is not found in the invoked String object.






Method lastIndexOf() to search the last index of a char in a String.


We are searching for the last index of a particular char value in a String object using LastIndexOf() method. If the searched char is found, its last index is returned, otherwise if the charis not found then -1 is returned.

// Program to find a particular character in a String.

class StringIndex1
{
public static void main(String[] ar)
{
String str1= new String("Java Rules, Java");

int index1 = str1.lastIndexOf('v');
int index2 = str1.lastIndexOf('a');
int index3 = str1.lastIndexOf('z');

System.out.println("Last Index of 'v' in " + str1 +  " : "+ index1);
System.out.println("Last Index of 'a' in " + str1 +  " : "+ index2);
System.out.println("Last Index of 'z' in " + str1 +  " : "+ index3);
}
}





Output is :




Last Index of 'v' in Java Rules, Java : 14
Last Index of 'a' in Java Rules, Java : 15
Last Index of 'z' in Java Rules, Java : -1





Program Analysis



String is initialized with value Java Rules, Java
• Index of the Last occurrence of char value v in the String object is found 14.
• Index of the Last occurrence of char value a in the String object is found 15.
• Index of the Last occurrence of char value z in the String object is not found, hence -1 is returned.







Method lastIndexOf() to search last index of a string in a String object.


Here in this next example, we are searching for the last index of a particular String value in a String object using indexOf() method. If the searched String is found, its last index is returned, otherwise if the String is not found then -1 is returned.

// Program to find a particular character in a String.

class StringIndex1
{
public static void main(String[] ar)
{
String str1= new String("Blue Sky Blue");

int index1 = str1.lastIndexOf("Blue");
int index2 = str1.lastIndexOf("Sky");
int index3 = str1.lastIndexOf("Hi");

System.out.println("Last Index of Blue in " + str1 +  " : "+ index1);
System.out.println("Last Index of Sky  in " + str1 +  " : "+ index2);
System.out.println("Last Index of Hi   in " + str1 +  " : "+ index3);
}
}





Output is :




Last Index of Blue in Blue Sky Blue : 9
Last Index of Sky  in Blue Sky Blue : 5
Last Index of Hi   in Blue Sky Blue : -1





Program Analysis



String is initialized with value Blue Sky Blue
• Index of the Last occurrence of String value Blue in the String object is found 9.
• Index of the Last occurrence of String value Sky in the String object is found 5.
• Index of the Last occurrence of String value Hi in the String object is not found, hence -1 is returned.





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Method lastIndexOf() performs a case-sensitive search.


Both forms of indexOf() method perform a case-sensitive search, whether it comes to the search of the last index of a char or String value in a String object.

// Program to find a particular character in a String.

class StringIndex1
{
public static void main(String[] ar)
{
String str1= new String("Toys Story"); 
String str2= new String("Live and let live");

int index1 = str1.lastIndexOf('s');
int index2 = str2.lastIndexOf("live");

System.out.println("Last Index of s    in " + str1 +  " : "+ index1);
System.out.println("Last Index of live in " + str2 +  " : "+ index2);
}
}





Output is :




Last Index of s    in Toys Story : 3
Last Index of live in Live and let live : 13





Program Analysis



First String is initialized with value Toys Story, second String is initialized with Live and let live.
• Index of the last occurrence of char value lower case s in the first String object is found 3.
• Index of the last occurrence of String value live in the second String object is found 13.





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