iOS数组元素进行 升序/降序 排序

NSMutableArray*priceArray=[NSMutableArray array];

        for (NSString*greadStr in greadPriceArr)

        {

//greadStr=1_10_100

            NSArray*dataArray=[greadStr componentsSeparatedByString:@"_"];

//把分割之后的元素转化成NSNumber 添加到另外一个数组内

            NSNumber * number = [NSNumber numberWithFloat:[[dataArray objectAtIndex:2] floatValue]];

            [priceArray addObject:number];

        }

//在对priceArray 数组进行升序操作

        NSArray *result = [priceArray sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {

            return [obj1 compare:obj2]; //升序

            return [obj2 compare:obj1]; //降序

        }];