从同一个float创建的两个NSNum根据==不相等 [英] Two NSNumbers created from the same float aren't equal according to ==

问题描述

我有一些 float s，我转换为 NSNumber s并添加到数组， $ float s，然后将它们转换为 NSNumber s，但如果我尝试比较他们 if（numinarray = newnum）{它从来没有去任何地方。当我 NSLog（）输出值时，值匹配：

  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：distance9]，
 [NSNumber numberWithFloat：distance10]，
 [NSNumber numberWithFloat：distance11]，
 [NSNumber numberWithFloat：distance12]零]; 
 
 sorted = [nums sortedArrayUsingSelector：@selector（comparison :)]; 
 
 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）; 
} 
  

使用 NSNumber ？

解决方案

而不是使用 == ，调用 比较： 或 isEqualToNumber： 。当您使用 == 时，您正在比较指针。

I have a few floats which I convert to NSNumbers and add to an array, then sort in numerical order.

I then take the original floats and convert those to NSNumbers, but if I try to compare them if(numinarray = newnum){ it never goes anywhere. When I NSLog() out the value, the values match:

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 with using NSNumber? If so, how would you get arround it?

解决方案

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

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