addObjectsFromArray to the beginning of an existing array

Question

I'm having trouble adding an existing array to the beginning of another array. For example: MutableID array contains 1,2,3,4,5 & idArray array contains 6,7,8

self.MutableID.addObjectsFromArray(idArray as [AnyObject])
//currently puts values to the end of the array not the beginning

this code outputs 1,2,3,4,5,6,7,8 but I want it to output 6,7,8,1,2,3,4,5

I need the values added to the beginning of self.MutableID Any suggestions on how I can accomplish this?

Possible duplicate of [NSMutableArray - Add array at start](http://stackoverflow.com/questions/22492706/nsmutablearray-add-array-at-start) — Ruben Steins, Dec 10 '15 at 13:42

score 0 · Answer 1 · answered Dec 10 '15 at 13:19

0

self.MutableID.insertContentsOf(idArray as [AnyObject], at: 0)

answered Dec 10 '15 at 13:19

fluidsonic

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NSMutableArray has no member insertConsentsOf – SlopTonio Dec 10 '15 at 13:22
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When you use Swift you shouldn't use `NSArray` and `NSMutableArray` directly. Use `var MutableID: [Int]` instead. – fluidsonic Dec 10 '15 at 13:23
You can't add objects from a `[AnyObject]` to a `[Int]`. – nhgrif Dec 10 '15 at 13:24
@SlopTonio If you *need* to use `NSMutableArray`, your question should make that clear with more than just the tags. – nhgrif Dec 10 '15 at 13:25
@nhgrif No need to cast `idArray` to `[AnyObject]` then. Or just use `var MutableID: [AnyObject]` if really necessary. – fluidsonic Dec 10 '15 at 13:25
I'm new to swift, why is it not recommended to use NSMutableArray directly? – SlopTonio Dec 10 '15 at 13:55
While this code may answer the question, providing additional context regarding why and/or how this code answers the question improves its long-term value. – ryanyuyu Dec 10 '15 at 15:47

score 0 · Answer 2 · edited May 23 '17 at 11:52

This question is the Swift version of this question which solves the problem in Objective-C.

If we must, for whatever reason, be using Objective-C's NSArray or NSMutableArray, then we can simply use a Swift translation of the code in my answer over there:

let range = NSMakeRange(0, newArray.count)
let indexes = NSIndexSet(indexesInRange: range)
oldArray.insertObjects(newArray as [AnyObject], atIndexes: indexes)

Where oldArray is an NSMutableArray and newArray is NSArray or NSMutableArray.

Or the other approach, append and reassign:

oldArray = newArray.arrayByAddingObjectsFromArray(oldArray as [AnyObject])

But the most correct thing to do would be to use the Swift Array type, and then use the insertContentsOf(_: Array, at: Int) method, as fluidsonic's answer describes.

score 0 · Accepted Answer · answered Dec 10 '15 at 13:50

NSMutableArray has insertObjects method.

self.MutableID.insertObjects(otherArray as [AnyObject], atIndexes: NSIndexSet(indexesInRange: NSMakeRange(0, otherArray.count)))

Or you can assign the mutable array to a swift array and use insertContentsOf method ;)

self.MutableID = NSMutableArray(array: [1,2,3,4])
var otherArray = NSMutableArray(array: [6,7,8,9])

var swiftArr : [AnyObject] = self.MutableID as [AnyObject]
swiftArr.insertContentsOf(otherArray as [AnyObject], at: 0)

addObjectsFromArray to the beginning of an existing array

3 Answers3