I have an array:
data.Dealer.car[0]
data.Dealer.car[1]
data.Dealer.car[2]
If I do this:
alert(data.Dealer.car.length);
delete data.Dealer.car[1];
alert(data.Dealer.car.length);
It gives me the same count each time. Does the removed element still exist?
If you want to remove an item, use the splice method:
alert(data.Dealer.car.length);
data.Dealer.car.splice(1, 1);
alert(data.Dealer.car.length);
But notice that the indices have changed.
JavaScript arrays aren't sparse, if you have a 0 and a 2, then element 1 must exist. Meaning the length is going to be 3.
let arr = ['foo' , , 'bar'] is a sparse array, so it has length 3, even though arr[1] does not have a value.Array.shift() would remove the first item from the array and make it shorter. Array.pop() will remove the last item.
Building on what @Ray Hidayat posted:
JavaScript arrays are sparse. If you have an array of length 3, deleting the reference at [1] will simply "unset" that item, not remove it from the array, or update that array's length. You could accomplish the same with
myArray = [0, , 2, , , , ]; // length 6; last three items undefined
Here's a Fiddle: http://jsfiddle.net/WYKDz/
NOTE: removing items from the middle of large arrays can be computationally intensive. See this post for more info: Fastest way to delete one entry from the middle of Array()
I think you're looking for this:
var arr = [0,1,2,3,4];
alert( arr.splice( 2, 1 ) ); // alerts 2, the element you're removing
alert( arr ) // alerts 0,1,3,4 - the remaining elements
here's a MDC reference
Ok.. fixed this now as the array was still allocated.
I needed to basically do:
var newCar = new Array();
for (i = 0 ; i < tblSize -2; i ++)
{
newCar[i]=data.Dealer.car[i];
}
data.Dealer.car = newCar;
deleteandArray.prototype.splice, whereas this question is basically asking why deleting an element from an array (thus making it sparse) won’t reduce its length.