Question

I’ve below numbers which are stored as NSCFString into SQLite

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These numbers converts perfectly

475602307163925662

1529228456639250520

I am converting these like, (NSNumber *) [myDictionary valueForKey:@"stringData"]; and its working perfectly

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These numbers couldn’t converts perfectly

14154269406789154303

13207084142614401684

12870871772958895646

I want to convert these NSCFString into NSNumber. I try using below code and google it but dont get exact solution as I want. Any help would be appriciated.

NSNumberFormatter *f=[[NSNumberFormatter alloc] init];
[f setNumberStyle:NSNumberFormatterDecimalStyle];
NSNumber *myNumber=[f numberFromString:[myDictionary valueForKey:@"stringData"]];
[f release];

but it converts my number something like 9.45214212452152

I tried some other way as well but its also not working well.

NSNumber *myNumber=[NSNumber numberWithLong:[myDictionary valueForKey:@"stringData"]];

Answer 1

Casting an object as another object (aka (NSNumber *)) does not “convert” it. It just promises the compiler that you’re working with an object of that class which you aren’t.

The reason why some numbers are totally failing is because they’re too large to fit in the standard int/float/long sizes. Instead of NSNumber, use NSDecimalNumber – a subclass of NSNumber (so you can still use all of the NSNumber methods as well). It’s specifically designed to handle large numbers:

NSDecimalNumber *number = [NSDecimalNumber decimalNumberWithString:<your string object>];