delete
will delete the object property, but will not reindex the array or update its length. This makes it appears as if it is undefined:
> myArray = ['a', 'b', 'c', 'd']
["a", "b", "c", "d"]
> delete myArray[0]
true
> myArray[0]
undefined
Note that it is not in fact set to the value undefined
, rather the property is removed from the array, making it appear undefined. The Chrome dev tools make this distinction clear by printing empty
when logging the array.
> myArray[0]
undefined
> myArray
[empty, "b", "c", "d"]
myArray.splice(start, deleteCount)
actually removes the element, reindexes the array, and changes its length.
> myArray = ['a', 'b', 'c', 'd']
["a", "b", "c", "d"]
> myArray.splice(0, 2)
["a", "b"]
> myArray
["c", "d"]
You want the splice
function on the native array object.
arr.splice(index, 0, item);
will insert item
into arr
at the specified index
(deleting 0
items first, that is, it's just an insert).
In this example we will create an array and add an element to it into index 2:
var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";
console.log(arr.join()); // Jani,Hege,Stale,Kai Jim,Borge
arr.splice(2, 0, "Lene");
console.log(arr.join()); // Jani,Hege,Lene,Stale,Kai Jim,Borge
Best Answer
Yes. As of Swift 3.0, if you need the index for each element along with its value, you can use the
enumerated()
method to iterate over the array. It returns a sequence of pairs composed of the index and the value for each item in the array. For example:Before Swift 3.0 and after Swift 2.0, the function was called
enumerate()
:Prior to Swift 2.0,
enumerate
was a global function.