javascript - Undefined when trying to get the upper bound of array? - Stack Overflow

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I was just thinking back to the good old days when I used to use VBScript (good old days?!?!? What am I thinking?), and I remember using two very useful methods with arrays, these were UBound and LBound. Now I don't think JavaScript has these and if I wanted to make my own I could extend the object however, I just tried doing this to return the upperbound item (or the last item of the array)

var myArray = ['1','2','3','4','5','6','seven', 8, 'nine','10'];
document.write(myArray.length + ' ' + myArray[myArray.length]);

the myArray.length returns what it should however when I try and output the last item using myArray[myArray.length] I get undefined? Anyone know why this is?

Thanks

I was just thinking back to the good old days when I used to use VBScript (good old days?!?!? What am I thinking?), and I remember using two very useful methods with arrays, these were UBound and LBound. Now I don't think JavaScript has these and if I wanted to make my own I could extend the object however, I just tried doing this to return the upperbound item (or the last item of the array)

var myArray = ['1','2','3','4','5','6','seven', 8, 'nine','10'];
document.write(myArray.length + ' ' + myArray[myArray.length]);

the myArray.length returns what it should however when I try and output the last item using myArray[myArray.length] I get undefined? Anyone know why this is?

Thanks

• javascript

Share Improve this question Follow edited Jun 18, 2014 at 13:49 Zong 6,23055 gold badges3333 silver badges4646 bronze badges asked Oct 15, 2011 at 11:10 Mark SandmanMark Sandman 3,3331212 gold badges4242 silver badges6161 bronze badges 2

• Javascript array starts with 0 – Rosdi Kasim Commented Oct 15, 2011 at 11:14
• And don't forget that there can also be undefined elements in the middle of the array. – nnnnnn Commented Oct 15, 2011 at 12:18

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2 Answers 2

Sorted by: Reset to default 6

The last element of myArray is at myArray.length - 1, since arrays in Javascript are 0-indexed. So , myArray[myArray.length -1] is what you're looking for.

The indexes start at 0. The last element is at myArray.length - 1

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