iOS-将数组内的模型对象排序

• 创建两个Person对象，并把它们放入数组，按年龄升序排序

Person *person1 = [[Person  alloc] init];
Person *person2 = [[Person  alloc] init];

person1.age = @"8";
person2.age = @"5";

NSMutableArray *arr = [NSMutableArray arrayWithObjects: person1, person2, nil];

NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES];

NSArray *newArr = [topArr sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];

此时newArr中，是以person2, person1的顺序存储。