C++ - 如何创建具有 4 个变量和 4 个键的多重映射
我想创建一个如下所示的类，
class enumClass
{
int msdnEnum;
std::string msdnEnumString;
int localEnum;
std::string localEnumString;
}
std::set<enumClass_Objects> enums; // all msdnEnums are unique, same aplies to other three.
enums.find(given_msdnEnum)->FourthVariable;
enums.find(given_localEnum)->FirstVariable;
enums.find(given_msdnEnumStr)->anyVariable;
enums.find(given_localEnumStr)->anyVariable;
我提到了 boost::multiIndex。但我认为这对这个案子没有帮助。有人能说出实现这一目标的方法吗？
编辑 我不太擅长阅读模板类。至于我所关心的，我在 multiIndex 中没有找到任何“查找”方法。我只看到了该示例中的整理内容（第一个基本示例：
I want to create a class like below
class enumClass
{
int msdnEnum;
std::string msdnEnumString;
int localEnum;
std::string localEnumString;
}
std::set<enumClass_Objects> enums; // all msdnEnums are unique, same aplies to other three.
enums.find(given_msdnEnum)->FourthVariable;
enums.find(given_localEnum)->FirstVariable;
enums.find(given_msdnEnumStr)->anyVariable;
enums.find(given_localEnumStr)->anyVariable;
I referred boost::multiIndex. But I don't think that it helps on this case. Can anybody say the way to achieve this?
EDIT
I am not that much good in reading template classes. As for as I am concerning I didn't find any "find" methods in multiIndex. I saw only sorting out things in that example(the first basic example:link). Suggestions&advices are always welcomed
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评论（3）
在这种情况下，boost multiindex 正是您所需要的。为四个键构建四个索引 - 我猜你保证它们都是唯一的，使它们成为唯一索引（我相信只有其中一个可以是 hashed_unique，但我认为你可以使其他三个 order_unique），然后执行您对每个索引的搜索取决于您搜索的内容。
boost multiindex is exactly what you need in this case. Construct four indexes for the four keys - I guess given you guarantee that they will all be unique, make them unique indexes (I believe only one of them can be hashed_unique, but I think you can make the other three ordered_unique), and then do your searches on the each index depending on what you are searching by.
这是一个使用 boost.multi_index 的简单示例：
标签类也可用于通过名称而不是序数索引来访问索引，其用法如下所示：
两种方法之间的差异纯粹是美学上的，当然还有标签类可以命名为您想要的任何名称，而不是
byMsdnEnum等。另请注意，可以使用散列索引而不是有序索引，这将使您的索引具有std::unordered_map的行为code> 而不是std::map。Here's a simple example using boost.multi_index:
Tag classes could be used to access the indices by name rather than ordinal index as well, usage of which would look like this:
The difference between the two approaches is purely aesthetic, and of course the tag classes could be named whatever you want rather than
byMsdnEnum, etc. Also note that hashed indices could be used rather than ordered indices, which would give your indices the behavior ofstd::unordered_maprather thanstd::map.有什么理由不能使用两张地图吗？ ( std::map)。如果您需要通过这两个键中的任何一个来查找两个字符串变量，那么您可以通过使用一个映射来解决它，例如将
msdnEnum与两个字符串配对，然后使用一个可以配对的映射localEnum与msdnEnum。通过msdnEnum进行的任何查找都将直接完成，而通过localEnum进行的查找将首先转换为msdnEnum，然后进行直接查找。Is there a reason why you cannot use 2 maps? ( std::map< int, std::string> ). If you need to find both of the string variables by any of those two keys, then you could solve it by having a map that would pair for example
msdnEnumwith both strings and then have a map that would pairlocalEnumwithmsdnEnum. Than any lookup viamsdnEnumwould be done directly and a lookup vialocalEnumwould first do a translation tomsdnEnumand then do a direct lookup.