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Re: Simple question
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Re: Simple question


  • Subject: Re: Simple question
  • From: Reinhard Segeler <email@hidden>
  • Date: Thu, 22 Apr 2010 18:31:48 +0200

Hi,

correct me if I'm wrong, but what you're doing is a calculation with the pointers ( * of NSNumber) not the values. You have to calculate it like this:

NSInteger fieldOne = [ [ managedObject valueForKey:@"key1"] intValue]; // if it's an integer
NSInteger fieldTwo = [ [ managedObject valueForKey:@"key2"] intValue];
NSInteger fieldThree = [ [ managedObject valueForKey:@"key3"] intValue];


if ( fieldTwo > 0 )
{
NSNumber *answer = [ NSNumber numberWithInt:fieldTwo - fieldOne + fieldThree];
[ self.managedObject setValue:answer forKey:@"key4"];
// maybe you need to this instead
[ self.managedObject setValue:[ answer stringValue] forKey:@"key4"];
}


Don't know if intValue in this context works, if not then use this alternative, which must work in any way:

Your code and change the following lines:

NSNumber *answer = [ NSNumber numberWithInt: [fieldTwo intValue] - [fieldOne intValue] + [fieldThree intValue] ];

	[ self.managedObject setValue:answer forKey:@"key4"];
	//or
	[ self.managedObject setValue:[ answer stringValue] forKey:@"key4"];
	//stringValue to present it in a textfield

Hope that helped... MacMeideln

Am 22.04.2010 um 17:36 schrieb Arnold Nefkens:

Hello list,

Im quite new, and probably missing something.

I want to do a calculation of three fields inside of a entity in CoreData.

Below is the code, what is wrong?

NSNumber *fieldOne = [managedObject valueForKey:@"key1"];
NSNumber *fieldTwo = [managedObject valueForKey:@"key2"];
NSNumber *fieldThree = [managedObject valueForKey:@"key3"];
if (fieldTwo > 0) {
	NSNumber *answer = ((fieldTwo - fieldOne) + fieldThree);
	[self.managedObject setValue:[answer intValue] forKey:@"key4"];
}

If I debug the right values are being shown in the fieldOne, fieldTwo and fieldThree. But the calculation answer is all the time out of scope.....

What am I missing?

hope someone can help...

Arnold Nefkens_______________________________________________

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