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iOS

Posted by Rashii Henry
Rashii Henry
16,433 Points

Passing integers into an array.

This is actually pretty simple and i may be over thinking but I'm having trouble passing in some integers into an array without Xcode throwing any errors in my face. 

NSMutableArray *scores = [[NSMutableArray alloc]initWithObjects:_redScore, _Bluescore, _purpleScore, _greenScore, nil];

is what i have s far but Xcode keeps telling me that implicit conversion from int to id is incompatible because of arc.

i just want to be able to have these integers into an array so i can't sort them from higest lowest.

Any suggestions would be great.

3 Answers

Justin Horner
STAFF
Justin Horner
Treehouse Guest Teacher
Justin Horner
Justin Horner
Treehouse Guest Teacher

Hello Rashii,

If the scores are integers, the issue is initWithObjects is expecting objects instead of primitive types.

Here is an example of how this could be done.

int x = 1;
int y = 2;

NSArray *array = [[NSArray alloc] initWithObjects:[NSNumber numberWithInt:x], [NSNumber numberWithInt:y], nil];

I hope this helps.

Rashii Henry
Rashii Henry
16,433 Points

one last question Justin, would i be able to use NSSortDescriptor to order those integers from highest to lowest?

Justin Horner
Justin Horner
Treehouse Guest Teacher
Justin Horner
Justin Horner
Treehouse Guest Teacher

Yes, you can use NSSortDescriptor to sort in descending order like this.

NSSortDescriptor *mySorter = [[NSSortDescriptor alloc] initWithKey:@"intValue" ascending:NO];
array = [array sortedArrayUsingDescriptors:[NSArray arrayWithObjects:mySorter, nil]];
Rashii Henry
Rashii Henry
16,433 Points
Rashii Henry
Rashii Henry
16,433 Points

how will the sort descriptor know what key to initialize with if i didn't store the integers with a key?

Justin Horner
Justin Horner
Treehouse Guest Teacher
Justin Horner
Justin Horner
Treehouse Guest Teacher

When the array is being sorted it will use the intValue function on NSNumber instances. That is the value it then uses for the sort.

I hope this helps.

Rashii Henry
Rashii Henry
16,433 Points
Rashii Henry
Rashii Henry
16,433 Points

thanks justing, you're helping a lot and I'm learning a lot.

here's what i implemented, however, i don't get the values in the console although i do get somethings:

NSArray *array = [[NSArray alloc] initWithObjects:[NSNumber numberWithInt:_redScore],[NSNumber numberWithInt:_Bluescore],[NSNumber numberWithInt:_purpleScore],[NSNumber numberWithInt:_greenScore], nil];

    NSSortDescriptor *mySorter = [[NSSortDescriptor alloc] initWithKey:@"intValue" ascending:NO];
    array = [array sortedArrayUsingDescriptors:[NSArray arrayWithObjects:mySorter, nil]];


    NSLog(@"%@", mySorter);

Now look here's what i've been getting in the console:

 (intValue, descending, compare:)
2014-06-16 00:25:31.850 Flocking Birds[7449:60b] (intValue, descending, compare:)
Caleb Viola
Caleb Viola
5,694 Points

array = [array sortedArrayUsingDescriptors:[NSArray arrayWithObjects:mySorter, nil]]; The sorted values are not being stored in mySorter but in the array variable.