Getting the last value of an Array and showing it

问题:

var NewdateData[] = [1,2,3,4,5,6,7,8,9,1,2,1,23,45,56]

This NewdateData is dynamically filled from database depending upon the selection made from the user interface.

I am using this NewdateData for displaying under the X axis Charts.

The issue I am facing is that, the values are not taken till the end , I want to have the last value to have under the X axis Labels.

xaxis: {tickFormatter: function(n)
{
    var k = Math.round(n);
    return NewdateData[k]; 
}

I am using flotr.

回答1:

You can get the last value of an array with:

NewdateData[NewdateData.length-1];

回答2:

Very late to the party, but for posterity: in ES2015/ES6 you can use Array.prototype.slice. Doesn't affect the array and a negative number gives you elements from the end of the array as a new array.

So to get the last element:

let arr = [1, 2, 3, 4, 5];
let last = arr.slice(-1)[0]; // last = 5