How to determine the true data type of an NSNumber?

Question

Consider this code:

NSNumber* interchangeId = dict[@\"interchangeMarkerLogId\"];
long long llValue = [interchangeId longLongValue];
double dValue = [intercha         


        

Answer 1

Ok--It's not 100% ideal, but you add a little bit of code to SBJSON to achieve what you want.

1. First, add NSNumber+SBJson to the SBJSON project:

NSNumber+SBJson.h

@interface NSNumber (SBJson)
@property ( nonatomic ) BOOL isDouble ;
@end

NSNumber+SBJson.m

#import "NSNumber+SBJSON.h"
#import 

@implementation NSNumber (SBJson)

static const char * kIsDoubleKey = "kIsDoubleKey" ;

-(void)setIsDouble:(BOOL)b
{
    objc_setAssociatedObject( self, kIsDoubleKey, [ NSNumber numberWithBool:b ], OBJC_ASSOCIATION_RETAIN_NONATOMIC ) ;
}

-(BOOL)isDouble
{
    return [ objc_getAssociatedObject( self, kIsDoubleKey ) boolValue ] ;
}

@end

2. Now, find the line in SBJson4StreamParser.m where sbjson4_token_real is handled. Change the code as follows:

case sbjson4_token_real: {
    NSNumber * number = @(strtod(token, NULL)) ;
    number.isDouble = YES ;
    [_delegate parserFoundNumber:number ];
    [_state parser:self shouldTransitionTo:tok];
    break;
}

note the bold line... this will mark a number created from a JSON real as a double.

3. Finally, you can check the isDouble property on your number objects decoded via SBJSON

HTH

edit:

(Of course you could generalize this and replace the added isDouble with a generic type indicator if you like)