CODEWITHSUNDEEP
objective-carraysif-statement
Taskinul Haque
Taskinul Haque

Reputation: 724

checking NSArray values

I have an NSArray (RSIatAddr), and I want to check whether the object at the given index = 0 (or some other arbitrary constant) but the following code gives me no warnings / error ; but is throwing an exception

if ([[RSIatAddr objectAtIndex:j] isEqualToNumber:nil]) {
    [sumRSI addObject:[NSNumber numberWithInt:[[RSIatAddr objectAtIndex:j]intValue]*
    [[sumRSI objectAtIndex:j] intValue]]]; }

The error I'm getting:

2012-10-02 00:42:00.266 NetSearch+DetectLocation[3741:707] 
*** Terminating app due to uncaught exception 
'NSInvalidArgumentException', reason: '-[__NSCFNumber compare:]: nil argument'

Upvotes: 0

Views: 184

Answers (2)

Russell Christensen
Russell Christensen

Reputation: 191

Without seeing the code that actually fills your array, its likely the array is holding a different type than you are expecting. Try setting a breakpoint right before that line of code, and typing "po [[RSIatAddr objectAtIndex:j] class]" and see what is actually there, then you can also try your isEqualToNumber in the debug window to see if that succeeds.

I just implemented this in the AppDelegate of a new iOS App and it works:

NSArray *array = [[NSArray alloc] initWithObjects:[NSNumber numberWithInt:0], [NSNumber numberWithInt:1], nil];
NSLog(@"%@", array);

for (NSNumber *num in array) {
    if ([num isEqualToNumber:[NSNumber numberWithInt:0]]) {
        NSLog(@"Equal");
    } else {
        NSLog(@"Not Equal");
    }
}

Upvotes: 1

jscs
jscs

Reputation: 64002

isEqualToNumber: takes an NSNumber as an argument, not the integer that you're passing.

The integer that you're using, 0, happens to be the value of nil, but any integer would be extremely unlikely to be a valid pointer value for an NSNumber, and would also therefore crash.

Upvotes: 3

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