LinkedList search
In this chapter you will learn:
- What are the methods from LinkedList we can use to do a search
- How to use the return value from indexOf and lastIndexof
- If contain a certain element
Methods to do the search
int indexOf(Object o)
Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.int lastIndexOf(Object o)
Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
import java.util.LinkedList;
/*from j ava2s. c om*/
public class Main{
public static void main(String args[]) {
LinkedList<String> ll = new LinkedList<String>();
ll.add("A");
ll.add("java2s.com");
ll.add("B");
ll.add("C");
ll.add("java2s.com");
System.out.println(ll.indexOf("java2s.com"));
System.out.println(ll.lastIndexOf("java2s.com"));
}
}
The output:
Return value from indexOf and lastIndexof
The following code uses indexOf
and lastIndexOf
to search elements in a LinkedList and check the return value.
import java.util.LinkedList;
/* j av a2 s .co m*/
public class Main {
public static void main(String[] args) {
LinkedList lList = new LinkedList();
lList.add("1");
lList.add("2");
lList.add("3");
lList.add("4");
lList.add("5");
lList.add("java2s.com");
int index = lList.indexOf("2");
if (index != -1) {
System.out.println("First index of 2: " + index);
} else {
System.out.println("LinkedList does not contain 2");
}
index = lList.lastIndexOf("2");
if (index != -1) {
System.out.println("Last index of 2: " + index);
} else {
System.out.println("LinkedList does not contain 2");
}
}
}
The output:
If contain a certain element
boolean contains(Object o)
Returns true if this list contains the specified element.
import java.util.LinkedList;
// j av a2s . c o m
public class Main{
public static void main(String args[]) {
LinkedList<String> ll = new LinkedList<String>();
ll.add("B");
ll.add("ja v a2s.com");
ll.addLast("E");
ll.add("F");
boolean b = ll.contains("ja v a2s.com");
System.out.println(b);
}
}
The output:
Next chapter...
What you will learn in the next chapter:
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