Two NSNumbers created from the same float are not equal according to ==

Question

I have several float that I convert to NSNumber and add to the array, and then sort in numerical order.

Then I take the original float and convert them to NSNumber s, but if I try to compare them if(numinarray = newnum){ , it will never be anywhere else. When I NSLog() is out of value, the values ​​correspond to:

 float distance = [barnardCastle distanceFromLocation:loc1] / 1000; float distance2 = [billingham distanceFromLocation:loc1] / 1000; float distance3 = [bishopAukland distanceFromLocation:loc1] / 1000; float distance4 = [cockerton distanceFromLocation:loc1] / 1000; float distance5 = [darlington distanceFromLocation:loc1] / 1000; float distance6 = [guisborough distanceFromLocation:loc1] / 1000; float distance7 = [hartlepool distanceFromLocation:loc1] / 1000; float distance8 = [middlesbrough distanceFromLocation:loc1] / 1000; float distance9 = [northallerton distanceFromLocation:loc1] / 1000; float distance10 = [redcar distanceFromLocation:loc1] / 1000; float distance11 = [stockton distanceFromLocation:loc1] / 1000; float distance12 = [yarm distanceFromLocation:loc1] / 1000; NSArray *nums, *sorted; nums = [NSArray arrayWithObjects: [NSNumber numberWithFloat:distance], [NSNumber numberWithFloat:distance2], [NSNumber numberWithFloat:distance3], [NSNumber numberWithFloat:distance4], [NSNumber numberWithFloat:distance5], [NSNumber numberWithFloat:distance6], [NSNumber numberWithFloat:distance7], [NSNumber numberWithFloat:distance8], [NSNumber numberWithFloat:distance9], [NSNumber numberWithFloat:distance10], [NSNumber numberWithFloat:distance11], [NSNumber numberWithFloat:distance12], nil]; sorted = [nums sortedArrayUsingSelector:@selector(compare:)]; NSLog(@"nums sorted"); NSLog(@"distance is %f",distance); NSNumber *intdist = [NSNumber numberWithFloat:distance]; NSNumber *intdist2 = [NSNumber numberWithFloat:distance2]; NSNumber *intdist3 = [NSNumber numberWithFloat:distance3]; NSNumber *intdist4 = [NSNumber numberWithFloat:distance4]; NSNumber *intdist5 = [NSNumber numberWithFloat:distance5]; NSNumber *intdist6 = [NSNumber numberWithFloat:distance6]; NSNumber *intdist7 = [NSNumber numberWithFloat:distance7]; NSNumber *intdist8 = [NSNumber numberWithFloat:distance8]; NSNumber *intdist9 = [NSNumber numberWithFloat:distance9]; NSNumber *intdist10 = [NSNumber numberWithFloat:distance10]; NSNumber *intdist11 = [NSNumber numberWithFloat:distance11]; NSNumber *intdist12 = [NSNumber numberWithFloat:distance12]; NSLog(@"int dist %@",intdist); NSLog(@"int dist2 %@",intdist2); NSLog(@"int dist3 %@",intdist3); NSLog(@"int dist4 %@",intdist4); NSLog(@"int dist5 %@",intdist5); NSLog(@"int dist6 %@",intdist6); NSLog(@"int dist7 %@",intdist7); NSLog(@"int dist8 %@",intdist8); NSLog(@"int dist9 %@",intdist9); NSLog(@"int dist10 %@",intdist10); NSLog(@"int dist11 %@",intdist11); NSLog(@"int dist12 %@",intdist12); nearestLoc = [[NSMutableArray alloc]init]; NSLog(@"about to loop"); for (int i=0; i < 12; i++) { Branches *branches = [[Branches alloc]init]; NSLog(@"looping"); NSNumber *index = [sorted objectAtIndex:i]; NSNumber *intdist = [NSNumber numberWithFloat:distance]; NSNumber *intdist2 = [NSNumber numberWithFloat:distance2]; NSNumber *intdist3 = [NSNumber numberWithFloat:distance3]; NSNumber *intdist4 = [NSNumber numberWithFloat:distance4]; NSNumber *intdist5 = [NSNumber numberWithFloat:distance5]; NSNumber *intdist6 = [NSNumber numberWithFloat:distance6]; NSNumber *intdist7 = [NSNumber numberWithFloat:distance7]; NSNumber *intdist8 = [NSNumber numberWithFloat:distance8]; NSNumber *intdist9 = [NSNumber numberWithFloat:distance9]; NSNumber *intdist10 = [NSNumber numberWithFloat:distance10]; NSNumber *intdist11 = [NSNumber numberWithFloat:distance11]; NSNumber *intdist12 = [NSNumber numberWithFloat:distance12]; NSLog(@"int dist %@",intdist); NSLog(@"int dist2 %@",intdist2); NSLog(@"int dist3 %@",intdist3); NSLog(@"int dist4 %@",intdist4); NSLog(@"int dist5 %@",intdist5); NSLog(@"int dist6 %@",intdist6); NSLog(@"int dist7 %@",intdist7); NSLog(@"int dist8 %@",intdist8); NSLog(@"int dist9 %@",intdist9); NSLog(@"int dist10 %@",intdist10); NSLog(@"int dist11 %@",intdist11); NSLog(@"int dist12 %@",intdist12); NSLog(@"index %@",index); if (index == intdist) { branches.branchLoc = @"Barnard Castle"; branches.distance = distance; [nearestLoc addObject:branches]; NSLog(@"adding barnard castle"); } if (index == intdist2) { branches.branchLoc = @"Billingham"; branches.distance = distance2; [nearestLoc addObject:branches]; NSLog(@"adding billingham"); } 

Am I missing something using NSNumber ? If so, how would you outline it?

Answer 1

Instead of using == call compare: or isEqualToNumber: When you use == , you are comparing pointers.

Answer 2

In a test in which you use a compare pointer, not a value!

NSNumber comparison should be done using

 if([numInArray compare:newNum] == NSOrderedSame) { // do something }