Array search from the end with lastIndexOf()

In this chapter you will learn:

How to search a Javascript array from the end

Array lastIndexOf()

lastIndexOf syntax:

lastIndexOf(itemToLookFor, optionalIndexToStartWith)

lastIndexOf() starts from the back of the array to do the search. lastIndexOf() returns the position of the item in the array or -1 if the item isn't in the array.

An identity comparison is used during comparing.

<!DOCTYPE html><!--from j  a va2 s.c  o  m-->
<html>
<head>
    <script type="text/javascript">
        var numbers = [1,2,3,4,5,4,3,2,1]; 
        document.writeln(numbers.lastIndexOf(4)); //5 
        document.writeln(numbers.lastIndexOf(4, 4)); //3 
        
        
        var person = { name: "JavaScript" }; 
        var people = [{ name: "JavaScript" }]; 
        
        var morePeople = [person]; 
        document.writeln(morePeople.indexOf(person)); //0 

       
    </script>
</head>
<body>
</body>
</html>

Click to view the demo

Next chapter...

What you will learn in the next chapter:

Array filter() filters array with the given function.

Array search from the end with lastIndexOf()

Array lastIndexOf()

Next chapter...

Array Type

Array creation

Array type detecting

Array iterate

Array Length

Add to Array

Array join

Array concat()

Array every method

Array search from start with indexOf()

Array search from the end with lastIndexOf()

Array filter

Array mapping

Array forEach

Array pop and push

Array shift()

Array reduce()

Array reduceRight()

Array reverse()

Array slice()

Array some()

Array splice()

Array sort()

Array toString()

Array unshift()