Find index of array object in array object

Question

As an example if I have this array:

_mode = [NSArray arrayWithObjects:
                      [NSArray arrayWithObjects:@"1", @"One", nil],
                      [NSArray arrayWithObjects:@"2", @"Two", nil],
                      [NSArray arrayWithObjects:@"3", @"Three", nil],
                      [NSArray arrayWithObjects:@"4", @"Four", nil],
                      [NSArray arrayWithObjects:@"5", @"Five", nil],
                      nil];

and I need to find which object of array _mode contains @"3" how would I do that? I have tried selectedIndex = [_mode indexOfObject:@"3"]; and selectedIndex = [[_mode objectAtIndex:0] indexOfObject:@"sta"]; but neither work.

Ken Thomases · Accepted Answer · 2012-04-08 17:46:04Z

9

[_mode indexOfObjectPassingTest:^(id obj, NSUInteger idx, BOOL *stop){
    return [[obj objectAtIndex:0] isEqualToString:@"3"];
}];

answered Apr 8, 2012 at 17:46

Ken Thomases

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6 Comments

nacho4d Over a year ago

Unless you know the object you are looking for is always at index 0 this approach will need an extra for loop inside the block

Jonas Schnelli Over a year ago

Nice solution. But be informed: Available in iOS 4.0, Mac OS X v10.6 and later.

Ken Thomases Over a year ago

@nacho4d, if the target is not necessarily at index 0, just use [obj containsObject:@"3"].

Ken Thomases Over a year ago

Sure it does a loop. You have to examine the elements somehow. The point is to not write that loop yourself if you can avoid it. The code will be more readable, more compact, and less prone to error.

Darren Over a year ago

The object is always at index 0 of the subarray. This works perfect. Thanks.

|

nacho4d · Accepted Answer · 2012-04-08 17:50:37Z

3

This is basically the same as Jonas Schnelli answer :)

for (NSArray *subarray in _mode){
    NSInteger index = [subarray indexOfObject:@"3"];
    if (index != NSNotFound) return subarray;
}

answered Apr 8, 2012 at 17:50

nacho4d

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Comments

Jonas Schnelli · Accepted Answer · 2012-04-08 17:38:35Z

2

like this?

for(NSArray *subarray in _mode) {
  for(NSString *str in subarray) {
   if([str isEqualToString:@"3"]) {
     return subarray; // returns the array within _mode that contains "3"
   }
  }
}

if you need the index:

for(NSArray *subarray in _mode) {
  for(NSString *str in subarray) {
   if([str isEqualToString:@"3"]) {
     return [mode indexOfObject:subarray];
   }
  }
}

answered Apr 8, 2012 at 17:38

Jonas Schnelli

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Comments

Nima Soroush · Accepted Answer · 2014-11-22 12:07:27Z

2

This gives a index of a dictionary which is in array.

for (NSDictionary *dict in self.yourArray ) {
    if ([anotherArray containsObject:[dict valueForKey:@"Key"]]) {
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:[self.yourArray indexOfObject:dict] inSection:section];
        NSLog(@"IndexPath is %@",indexPath);
    }    
}

edited Nov 22, 2014 at 12:07

Nima Soroush

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answered Nov 22, 2014 at 11:01

ManishRathore

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