集合与可变集合排序（自己使用）

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //字符串进行排序
        NSArray *arr=@[@"b",@"a",@"c"];
        NSSortDescriptor *ns=[NSSortDescriptor sortDescriptorWithKey:nil ascending:YES];
        NSArray *B=[arr sortedArrayUsingDescriptors:@[ns]];
        NSLog(@"%@",B);

        //代码块排序
      NSArray *a=  [arr sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
            return [obj1 compare:obj2];
      }];
        NSLog(@"%@",a);
        //选择器排序
        NSArray *C=[arr sortedArrayUsingSelector:@selector(compare:)];
        NSLog(@"%@",C);

    }
    return 0;

}

   //可变集合的排序
        NSMutableArray *arr=[NSMutableArray array];
        [arr addObject:@"v"];
        [arr addObject:@"b"];
        [arr addObject:@"A"];
        //选择器排序
        [arr sortUsingSelector:@selector(compare:)];
        NSLog(@"%@",arr);
        //代码块排序
        [arr sortUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
            return [obj1 compare:obj2];
        }];
        NSLog(@"%@",arr);
        //描述信息排序
        NSSortDescriptor *nsSort=[NSSortDescriptor sortDescriptorWithKey:nil ascending:YES];
        [arr sortUsingDescriptors:@[nsSort]];
        NSLog(@"%@",arr);