sortedArrayUsingComparator

    /*
     升序、降序
     */
    NSArray * array41 = @[@4,@5,@2,@6,@3,@7,@8];
    NSArray * array42 = [[NSArray alloc]init];
    array42 = [array41 sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        
        NSNumber *tNumber1 = (NSNumber *)obj1;
        NSNumber *tNumber2 = (NSNumber *)obj2;
        //降序8，7，。。
//        if ([tNumber1 integerValue] < [tNumber2 integerValue]){
//            return NSOrderedDescending;
//        }
//        return NSOrderedAscending;
        //升序2，4，。。
        if ([tNumber1 integerValue] < [tNumber2 integerValue])
            return NSOrderedAscending;
        return NSOrderedDescending;
    }];
    NSLog(@"%@",array42);