2D Array Objective-C

Question

I'm creating an array from two mutable arrays. Array 1 has 3 objects and so does array 2 I'm receiving a crash that says "unrecognized selector sent to instance'" Why doesn't this work?

The two arrays are initialised:

self.array1 =[[NSMutableArray alloc]initWithObjects:@"word", @"word2", nil];
self.array2 =[[NSMutableArray alloc]initWithObjects:@"this goes with word1", @"this goes with the second word", nil];

NSMutableArray *objects;
for (int i=0 ; i<[array1 count]; i++){
   for (int j=0 ; j<[array2 count]; j++){
       objects = [[NSMutableArray alloc]init];
       objects=[array1 objectAtIndex:i][[array2 objectAtIndex:j]];
   }
}

What are you trying to do on this line: objects=[array1 objectAtIndex:i][[array2 objectAtIndex:j]]; ? — John
– John, Commented Apr 5, 2014 at 7:19
Show where you create and populate these arrays (which don't appear related to each other from your code) — Wain
– Wain, Commented Apr 5, 2014 at 7:20
objects=[array1 objectAtIndex:i][[array2 objectAtIndex:j]]; <-what is this ? — user3278923
– user3278923, Commented Apr 5, 2014 at 7:22
I'm trying to create something so that when the word is referenced in the first array, the second prints the information. — user3219182
– user3219182, Commented Apr 5, 2014 at 7:39

user816328 · Accepted Answer · 2014-04-05 08:11:18Z

1

If I understand you correctly you need to use a dictionary to provide the sort of lookup mechanism you want:

self.array1 = @[@"word", @"word2"].mutableCopy;
self.array2 = @[@"this goes with word1", @"this goes with the second word"].mutableCopy;

NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:self.array2
                                                       forKeys:self.array1];

NSLog(@"%@", dictionary[@"word"]);
// Prints "this goes with word1".

answered Apr 5, 2014 at 8:11

user816328

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Comments

mohitdream4u · Accepted Answer · 2014-04-05 07:22:23Z

0

use this:

NSMutableArray *objects = [[NSMutableArray alloc]init];
for (int i=0 ; i<[array1 count]&&[array2 count]; i++){

    [objects addObject:[NSString stringWithFormat:@"%@%@",[array1 objectAtIndex:i],[array2 objectAtIndex:i]]];
}

answered Apr 5, 2014 at 7:22

mohitdream4u

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1 Comment

davidkonrad Over a year ago

Why should OP do that? Try to explain.

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