Replace NAN value in order to avoid Crash

Question

I am drawing pie-charts using HighChart Library (Pie-chart). While Passing data to chart my code is like this :

 pie.data = [NSMutableArray arrayWithObjects:@{
                                                      @"name": @"New Jersey",
                                                      @"y": self->numPlusNJ
                                                      },
                    @{
                      @"name": @"Miami FLG",
                      @"y": self->numPlusMiamiFLG
                      },
                    @{
                      @"name": @"Chicago",
                      @"y": self->numPlusChicago
                      },nil];

where the values like self->numPlusNJ are NSNumbers. Sometimes after calculations value like 0(zero) comes in NSNumbers and it is taking those values as NAN. In those cases I am getting this error while drawing pie-chart :

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Invalid number value (NaN) in JSON write'.

I tried to Replace NAN value by 0 like this :

if(isnan([self->numRPercentNJ doubleValue])){self->numRPercentNJ = 0;}

But in that case I am getting can't insert nil in dictionary object.

So, Currently I am unsure about how to replace this NAN value by something in order to avoid crash.

Answer 1

Assuming your numbers (numPlusMiamiFLG, etc.) are properties on your current class, I'd suggest implementing an accessor for each one:

- (NSNumber *)numPlusMiamiFLG
{
    // Check if NaN
    if ([[NSDecimalNumber notANumber] isEqualToNumber: _numPlusMiamiFLG] {
        return [NSNumber numberWithDouble:0]; // Or whatever default
    } else {
        return _numPlusMiamiFLG;
    }
}

There's a chance you are not initializing your numbers correctly if you are getting nil/NaN. So I would double-check them.

Also note that the -> is not supposed to be used on Objective-C classes. As seen in this SO question.