NSSortDescriptor对象集合排序

 需求描述：一个数据源集合中含有多个对象(model),对象里含有多个业务属性字段比如价格，时间戳等。现在需要对集合里所有的对象进行价格1.从低到高的排序2.时间从近到远排序。
苹果官方有提供便利的排序NSSortDescriptor

    Model *m1 = [Model new];
    m1.price = 101;
    m1.time= @"2020-10-01";
    
    
    Model *m2 = [Model new];
    m2.price = 100;
    m2.time= @"2020-10-02";
    
    
    Model *m3 = [Model new];
    m3.price = 101;
    m3.time= @"2020-10-02";
    
    NSMutableArray *array = [NSMutableArray arrayWithObjects:m1,m2,m3, nil];
    NSLog(@"---begin%@\n",array);
    NSSortDescriptor *priceSort = [[NSSortDescriptor alloc]initWithKey:@"price" ascending:YES];
    NSSortDescriptor *timeSort = [[NSSortDescriptor alloc]initWithKey:@"time" ascending:YES];
    [array sortUsingDescriptors:@[priceSort,timeSort]];
    NSLog(@"---end%@\n",array);

排序前

image.png

排序后价格低->高在价格的基础上在按照时间近->进行排序

image.png

NSSortDescriptor *Sort = [[NSSortDescriptor alloc]initWithKey:@"key" ascending:(BOOL)ascending];
key 是对象里的属性，如果找不到属性会crash，ascending是否为升序排序.多个条件排序可累加。