Xcode 目标c使用NSSortDescriptor进行简单分类

我想在nslog中进行简单排序，这是我的viewcontroller。 -（无效）viewDidLoad{ [超级视图下载]

sobj=[[SortObjects alloc]init];

sobj.description;  //this doesn't work

[sobj description];//this doesn't work either

NSLog(@"sobj = %@", sobj);

}`

&这是我的对象类SortObjects.h

enter code here- (NSString *)description {
return [NSString stringWithFormat:@"%@ %@", self.firstName, self.lastName];
NSArray *firstNames = @[ @"Alice", @"Bob", @"Charlie", @"Quentin" ];
NSArray *lastNames = @[ @"Smith", @"Jones", @"Smith", @"Alberts" ];
NSArray *ages = @[ @24, @27, @33, @31 ];

NSMutableArray *people = [NSMutableArray array];
[firstNames enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    SortObjects *sObjects = [[SortObjects alloc] init];
    sObjects.firstName = [firstNames objectAtIndex:idx];
    sObjects.lastName = [lastNames objectAtIndex:idx];
    sObjects.age = [ages objectAtIndex:idx];
    [people addObject:sObjects];
}];

NSSortDescriptor *firstNameSortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"firstName"
                                                                          ascending:YES
                                                                           selector:@selector(localizedStandardCompare:)];
NSSortDescriptor *lastNameSortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"lastName"
                                                                         ascending:YES
                                                                          selector:@selector(localizedStandardCompare:)];
NSSortDescriptor *ageSortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"age"
                                                                    ascending:NO];

NSLog(@"By age: %@", [people sortedArrayUsingDescriptors:@[ageSortDescriptor]]);

---

sobj的值在nslog中变为空？？？

您从

说明
返回
self.firstName，self.lastName
，此时未设置该值。因此，您得到了
”
“@vadian对于空值是正确的，您希望在模型对象中存储所有类型（名称、姓氏和年龄）的排序值。你们能确认一下吗？那个么下一步该怎么做才能得到结果呢？