map

问题 I have an abstract class element and a child class elasticFrame : class element { public: virtual Matrix getStiffness() = 0; protected: Matrix K; }; class elasticFrame3d:public element { public: elasticFrame3d(double E, double G); virtual Matrix getStiffness(); virtual Matrix getTransform(); private: double E, G; }; what I want is to make a map like this: map<int, element> elementMap; but when I get this error: error C2259: 'element' : cannot instantiate abstract class is it even possible to

问题 Is it possible to create a generic method or class to retrieve an enum value from a given unique property (field with getter method)? So you would have: public enum EnumToMap { E1("key1"), E2("key2"), ; private final String key; private EnumToMap(String key) { this.key = key; } public String getKey() { return key; } } so required is the same functionality as public static EnumToMap getByKey(String key) ... would provide. Preferably without reflection and as generic as possible (but in this

问题 Is it possible to create a generic method or class to retrieve an enum value from a given unique property (field with getter method)? So you would have: public enum EnumToMap { E1("key1"), E2("key2"), ; private final String key; private EnumToMap(String key) { this.key = key; } public String getKey() { return key; } } so required is the same functionality as public static EnumToMap getByKey(String key) ... would provide. Preferably without reflection and as generic as possible (but in this

问题 Given: Map<WebSocket,String> mListUser; mListUser= new Map<WebSocket,String>(); From what i understood now to add a new element i should just do: mListUser[socket]="string"; instead im getting: type 'String' is not a subtype of type 'int' of 'index'. What am i doing wrong? 回答1: Maybe it helps final test = Map<String, int>(); test.putIfAbsent('58', () => 56); if key doesn't exist, it will be putted into map. 回答2: Maybe it helps. Map<Object,String> map1= new Map<Object,String>(); Collections c

问题 Given: Map<WebSocket,String> mListUser; mListUser= new Map<WebSocket,String>(); From what i understood now to add a new element i should just do: mListUser[socket]="string"; instead im getting: type 'String' is not a subtype of type 'int' of 'index'. What am i doing wrong? 回答1: Maybe it helps final test = Map<String, int>(); test.putIfAbsent('58', () => 56); if key doesn't exist, it will be putted into map. 回答2: Maybe it helps. Map<Object,String> map1= new Map<Object,String>(); Collections c

问题 I would like to have an std::map (int .NET 4.0). We of course know that a map is a tree and requires an operator< that string does not define for us. Error 24 error C2676: binary '<' : 'const std::string' does not define this operator or a conversion to a type acceptable to the predefined operator c:\program files\microsoft visual studio 10.0\vc\include\xfunctional 125 1 FXCMMarketDataServer So I put my google-foo to work and found this solution: struct StringComparerForMap { public: bool

问题 I would like to have an std::map (int .NET 4.0). We of course know that a map is a tree and requires an operator< that string does not define for us. Error 24 error C2676: binary '<' : 'const std::string' does not define this operator or a conversion to a type acceptable to the predefined operator c:\program files\microsoft visual studio 10.0\vc\include\xfunctional 125 1 FXCMMarketDataServer So I put my google-foo to work and found this solution: struct StringComparerForMap { public: bool

问题 I would like to have an std::map (int .NET 4.0). We of course know that a map is a tree and requires an operator< that string does not define for us. Error 24 error C2676: binary '<' : 'const std::string' does not define this operator or a conversion to a type acceptable to the predefined operator c:\program files\microsoft visual studio 10.0\vc\include\xfunctional 125 1 FXCMMarketDataServer So I put my google-foo to work and found this solution: struct StringComparerForMap { public: bool

问题 I'm bringing back a GD Image which is generated from user information in a database, now on the page where this image is viewed. I have the following area map for the image generated by the same sort of query to create a link to that users profile. However, there are a possible 40000 users in the database... anyway, what I have IS working, but as you can imagine it takes a long while for it to load. <map id="pixel" name="pixel"> <? $map_x_1 = 0; $map_y_1 = 0; $map_x_2 = 5; $map_y_2 = 5;

问题 I'm trying to use pig to break text into lowercased words, and then look up each word in a map. Here's my example map, which I have in map.txt (it is only 1 line long): [this#1.9,is#2.5my#3.3,vocabulary#4.1] I load this like so: M = LOAD 'mapping.txt' USING PigStorage AS (mp: map[float]); which works just fine. Then I do the following to load the text and break it into lowercased words: LINES = LOAD 'test.txt' USING TextLoader() AS (line:chararray); TOKENS = FOREACH LINES GENERATE FLATTEN