Objective-C: Format of NSArray vs NSMutable Array

Question

I'm using the Quickblox API to create group chats, which requires UserID's to be sent to methods using the following format:

NSArray *usersIDs = @[@(55), @(678), @(22)];

This array outputs to the log as such:

Correct Format: (
        55,
        678,
        22
)

In my app, I'm filling the array of User ID's to an NSMutableArray, as such:

[holderArray addObject:[users valueForKey:@"ID"]]

Which outputs to the log like this (which, when I send to the method, isn't working):

My Array: (
        (
        55
    ),
        (
        678
    ), (
        22
    ),
)

Can someone please explain what I'm doing wrong with the holderArray, and how I can get the objects to add in the correct format?

EDIT:

Here is the log output of the users NSArray:

users: (
    "
  [QBUUser]:
  ID:55
  created at:2015-08-27 19:33:24 +0000
  updated at:2015-08-27 19:33:24 +0000
  externalUserID:0
  blobID:0
  facebookID:(null)
  twitterID:(null)
  full name:(null)
  email:(null)
  login:3065555555
  phone:(null)
  tags:(null)
  lastRequestAt:2015-08-29 22:49:34 +0000
  customData:(null)
  website:(null)"
)

Well it looks like the type of [users valueForKey:@"ID"] is NSArray. Only you can confirm. — trojanfoe
– trojanfoe, Commented Aug 31, 2015 at 18:05
why are you using valueForKey? Cant you do something simple like [holderArray addObject:[users objectAtIndex:0]]; ? — Teja Nandamuri
– Teja Nandamuri, Commented Aug 31, 2015 at 18:05
@T_77 He could be using KVC or it could be a dictionary. Either way, objectAtIndex: will not work. — trojanfoe
– trojanfoe, Commented Aug 31, 2015 at 18:06
@trojanfoe: yes, users is an NSArray. holdersArray is an NSMutableArray — Adam G
– Adam G, Commented Aug 31, 2015 at 18:10

trojanfoe · Accepted Answer · 2015-08-31 18:26:49Z

3

There is nothing wrong with passing an NSMutableArray, given that it's a subclass of NSArray, the issue is with whatever [users valueForKey:@"ID"] returns, as it looks like an NSArray itself.

From the follow-up comments it looks like it's an NSArray of NSDictionary objects, so users valueForKey: will return all the IDs in the dictionaries. If that's true then just add them to holderArray using addObjectsFromArray:

NSArray *idents = [users valueForKey:@"ID"];
[holderArray addObjectsFromArray:idents];

edited Aug 31, 2015 at 18:26

answered Aug 31, 2015 at 18:10

trojanfoe

123k23 gold badges219 silver badges249 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Adam G Over a year ago

actually, using the code above I'm getting an error: expected method to read dictionary element not found on object of type nsarray

trojanfoe Over a year ago

@AdamG Yes; your original use of valueForKey: was correct. Fixed.

Collectives™ on Stack Overflow

Objective-C: Format of NSArray vs NSMutable Array

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related