Java StringBuilder.lastIndexOf() – Examples
In this tutorial, we will learn about the Java StringBuilder.lastIndexOf() function, and learn how to use this function to find the index of last occurrence of given string in this StringBuilder sequence, with the help of examples.
lastIndexOf(String str)
StringBuilder.lastIndexOf() returns the index within this string of the last occurrence of the specified substring.
Syntax
The syntax of lastIndexOf() function is
lastIndexOf(String str)
where
| Parameter | Description |
|---|---|
| str | The string to search for, in StringBuilder sequence. |
Returns
The function returns an integer.
Example 1 – lastIndexOf(str)
In this example, we will create a StringBuilder with some initial value. We will then find the index of last occurrence of the string “abc” in the StringBuilder sequence using lastIndexOf() method.
Java Program
public class Example {
public static void main(String[] args) {
StringBuilder stringBuilder = new StringBuilder("abcdefabcdefabcdef");
String str = "abc";
int index = stringBuilder.lastIndexOf(str);
System.out.println("Last index is : " + index);
}
} Output
Last index is : 12
Example 2 – lastIndexOf(str) – str not present
In this example, we will take a string, str, such that it is not present in StringBuilder sequence. In such case, StringBuilder.lastIndexOf(str) should return -1.
Java Program
public class Example {
public static void main(String[] args) {
StringBuilder stringBuilder = new StringBuilder("abcdefabcdefabcdef");
String str = "abd";
int index = stringBuilder.lastIndexOf(str);
System.out.println("Last index is : " + index);
}
} Output
Last index is : -1
lastIndexOf(String str, int fromIndex)
StringBuilder.lastIndexOf() returns the index within this StringBuilder sequence, of the last occurrence of the specified string, searching backward starting at the specified fromIndex.
In other words, search has to happen until given fromIndex in the StringBuilder sequence.
Syntax
The syntax of lastIndexOf() function is
lastIndexOf(String str, int fromIndex)
where
| Parameter | Description |
|---|---|
| str | The string to search for, in StringBuilder sequence. |
| fromIndex | The index in StringBuilder sequence, from which search has to happen towards the left. |
Returns
The function returns an integer.
Example 3 – lastIndexOf(str, fromIndex)
In this example, we will take a string and find its last occurrence in a StringBuilder, where the search has to happen only until the index 10.
Java Program
public class Example {
public static void main(String[] args) {
StringBuilder stringBuilder = new StringBuilder("abcdefabcdefabcdef");
String str = "abc";
int fromIndex = 10;
int index = stringBuilder.lastIndexOf(str, fromIndex);
System.out.println("Last index is : " + index);
}
} Output
Last index is : 6
Example 4 – lastIndexOf(str, fromIndex)
In this example, we will take an index and string, such that string has no occurrence in the subsequence. StringBuilder.lastIndexOf(str, fromIndex) should return -1.
Java Program
public class Example {
public static void main(String[] args) {
StringBuilder stringBuilder = new StringBuilder("abcdefabcdefabcdef");
String str = "ef";
int fromIndex = 3;
int index = stringBuilder.lastIndexOf(str, fromIndex);
System.out.println("Last index is : " + index);
}
} Output
Last index is : -1
Conclusion
In this Java Tutorial, we have learnt the syntax of Java StringBuilder.lastIndexOf() function, and also learnt how to use this function with the help of examples.