How would I loop through the NSMuttableArray, to check if an ID is same with a particular user id.?

Question

I want a looping concept in order to find whether an id in my code is matched or same as that of already present in the array.(for example I want to check whether the id 12345 is present in the following NSMutableArray) and also wants to know on which index path it has occurred and how to change that

{
    artist = "Green Day";
    id = 1421768;
    name = "American Idiot";
    releasedate = "21 Sep 2004";
    runningtime = "57.53";
    tracks = "1: American Idiot\n2: Jesus of Suburbia\n3: Holiday/Boulevard Of Broken Dreams\n4: Are We The Waiting/St. Jimmy\n5: Give Me Novacaine/She's A Rebel\n6: Extraordinary Girl/Letterbomb\n7: Wake Me Up When September Ends\n8: Homecoming\n9: Whatsername\n";
    trackscount = 9;
    type = 1;
},
    {
    artist = Bastille;
    id = 309124896;
    name = "Bad Blood";
    releasedate = "1 Mar 2013";
    runningtime = "43.98";
    tracks = "1: Pompeii\n2: Things We Lost in the Fire\n3: Bad Blood\n4: Overjoyed\n5: These Streets\n6: Weight of Living, Pt. II\n7: Icarus\n8: Oblivion\n9: Flaws\n10: Daniel in the Den\n11: Laura Palmer\n12: Get Home\n13: Weight of Living, Pt. I\n";
    trackscount = 13;
    type = 1;
},
    {
    artist = "Lacuna Coil";
    id = 2025689;
    name = Comalies;
    releasedate = "16 Oct 2012";
    runningtime = "51.75";
    tracks = "1: Swamped\n2: Heaven's a Lie\n3: Daylight Dancer\n4: Humane\n5: Self Deception\n6: Aeon\n7: Tight Rope\n8: The Ghost Woman and the Hunter\n9: Unspoken\n10: Entwined\n11: The Prophet Said\n12: Angels Punishment\n13: Comalies\n";
    trackscount = 13;
    type = 1;
}

Possible duplicate of [Filtering NSArray of NSDictionary objects using NSPredicate](https://stackoverflow.com/questions/10505154/filtering-nsarray-of-nsdictionary-objects-using-nspredicate) — Vishnu gondlekar, May 29 '17 at 10:13
Considering that "id" value is a NSString object: `NSUInteger index = [array indexOfObjectPassingTest:^BOOL(NSDictionary * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) { return [obj[@"id"] isEqualToString:@"3091248962"];}]; if (index == NSNotFound){ NSLog(@"Not found"); } else { NSLog(@"Index Found: %@", @(index)); }`. — Larme, May 30 '17 at 09:54

Pramod Tapaniya · Answer 1 · 2017-05-29T12:31:37.480

0

int index = -1;     
for (int i=0; i< [arrJSON count]; i++){
    NSDictionary *dict = [arrJSON objectAtIndex:i];

    if ([[dict objectForKey:@"id"] isEqualToString:@"123456"]){
       NSLog(@"Found at index: %d",i);
       index = i;
       break;
    }
}
if (index == -1){
    NSLog(@"ID not found");
}

edited May 29 '17 at 12:31

answered May 29 '17 at 10:14

Pramod Tapaniya

1,228
11
30

1

This is also another way to solve this issue. But for loop is faster than predicates when the number of entries in the array is too large. If you don't have a complex UI in your app, both approaches work equally fine – Arun May 29 '17 at 10:25
@Pramod Tapaniya....thnkuu donee....but I also want to get the information on which index it occurs(index path)...any answers – Roby May 29 '17 at 10:27
@Arun i have to use for loop now because Roby want to index also. :) – Pramod Tapaniya May 29 '17 at 11:00
@Roby check answer. – Pramod Tapaniya May 29 '17 at 11:00
@Roby if my answer solve your problem than accept as a correct answer. – Pramod Tapaniya May 29 '17 at 11:04
Maybe better to use `NSUInteger` and `NSNotFound` instead of `int` and `-1`. – Larme May 29 '17 at 18:40

Arun · Answer 2 · 2017-05-30T08:36:51.727

-2

BOOL isIDPresent = NO;
NSInteger index = 0;
for(; index < songsArray.count; index++) {
   NSDictionary *songDict = [songsArray objectAtIndex:index];
   if ([sondDict objectForKey:@"id"] == songId) {
      isIDPresent = YES;
      break;
  }
}
if (isIDPresent == YES) 
   NSLog(@"ID found at index : %d",index);
else
   NSLog(@"ID NOT FOUND");

where songsArray is the NSMutableArray and songId is the id you want to search for. The above code is valid when id is not a string. Check the code below if id is NSString

BOOL isIDPresent = NO;
NSInteger index = 0;
for(; index < songsArray.count; index++) {
   NSDictionary *songDict = [songsArray objectAtIndex:index];
   if ([[sondDict objectForKey:@"id"] isEqualToString:songId]) {
      isIDPresent = YES;
      break;
  }
}
if (isIDPresent == YES) 
   NSLog(@"ID found at index : %d",index);
else
   NSLog(@"ID NOT FOUND");

edited May 30 '17 at 08:36

answered May 29 '17 at 10:13

Arun

1,391
1
10
29

i think for loop is not proper way. – Pramod Tapaniya May 29 '17 at 10:16
Sorry for the mistake. Thanks @PramodTapaniya – Arun May 29 '17 at 10:22
1

In objective C, string comparission is not done by `==` operator – Saheb Roy May 29 '17 at 12:14
@SahebRoy From the data given in question, id doesn't looks like a string. That is why I gave == If it is a string you can use [[sondDict objectForKey:@"id"] isEqualToString: songId] instead – Arun May 29 '17 at 12:16
Edit your answer accordingly, as OP might find it usefull. – Saheb Roy May 29 '17 at 12:20
@Arun `[sondDict objectForKey:@"id"]` is an object, since you can only put objects into a NSDictionary. So `if ([[sondDict objectForKey:@"id"] isEqual: songId])` at least? – Larme May 29 '17 at 13:28
1

This algorithm performs *two* passes over the array - `for` and `indexOfObject:`- when only one is required. – CRD May 29 '17 at 17:53
Sorry but your edited version will always return that the item was found provided the array is non-empty, even if the item is not in the array. – CRD May 30 '17 at 08:31

How would I loop through the NSMuttableArray, to check if an ID is same with a particular user id.?

2 Answers2