map

问题 Here's a description: It operates like a regular map with get , put , and remove methods, but has a getTopKEntries(int k) method to get the top-K elements, sorted by the key: For my specific use case, I'm adding, removing, and adjusting a lot of values in the structure, but at any one time there's approximately 500-1000 elements; I want to return the entries for the top 10 keys efficiently. I call the put and remove methods many times. I call the getTopKEntries method. I call the put and

问题 I am using org.eclipse.jetty.util.ajax.JSON to parse JSON text. But the JSON.parse(string) method produces an Object and I need it as a Map. Internally it is an object of exactly the mentioned class. But how do you cast an Object into a Map without constructing a new one or getting the unchecked cast warning? Currently, I have found only one solution without the unchecked cast warning, but with constructing a new Map, which is actually of course not a casting at all. private Map<String,Object

问题 I am using org.eclipse.jetty.util.ajax.JSON to parse JSON text. But the JSON.parse(string) method produces an Object and I need it as a Map. Internally it is an object of exactly the mentioned class. But how do you cast an Object into a Map without constructing a new one or getting the unchecked cast warning? Currently, I have found only one solution without the unchecked cast warning, but with constructing a new Map, which is actually of course not a casting at all. private Map<String,Object

问题 When I make a std::map<my_data_type, mapped_value> , what C++ expects from me is that my_data_type has its own operator< . struct my_data_type { my_data_type(int i) : my_i(i) { } bool operator<(const my_data_type& other) const { return my_i < other.my_i; } int my_i; }; The reason is that you can derive operator> and operator== from operator< . b < a implies a > b , so there's operator> . !(a < b) && !(b < a) means that a is neither less than b nor greater than it, so they must be equal. The

问题 Total newb question. Say I have 2 maps val map1 = Map("ram"->"2gb", "size"->"15", "color"->"red", "fruit"->"strawberry") val map2 = Map("ram"->"2gb", "size"->"15", "color"->"red") and I want to know if map1 fully contains map2 (extra key/values in map1 are okay), what's a good Scala way to do that? The best I could come up with was to create my own function: def doesMapContainMap(map1: Map[_,_], map2: Map[_,_]): Boolean = { var matchCount: Int = 0 map2 foreach { entry => { if (map1.exists(x =

问题 I have the following class: struct EdgeExtended { int neighborNodeId; int weight; int arrayPointer; bool isCrossEdge; }; I want to have a vector of such objects, sort it by neighborNodeId. Then I want to search for a particular neighborNodeId and return a reference to the found object inside the vector by binary search. Previously I used a map for that, so it was something like that: map<int, EdgeExtended> neighbours; ..... auto it = neighbours.find(dnodeId); if (it != neighbours.end()) {

问题 I have the following class: struct EdgeExtended { int neighborNodeId; int weight; int arrayPointer; bool isCrossEdge; }; I want to have a vector of such objects, sort it by neighborNodeId. Then I want to search for a particular neighborNodeId and return a reference to the found object inside the vector by binary search. Previously I used a map for that, so it was something like that: map<int, EdgeExtended> neighbours; ..... auto it = neighbours.find(dnodeId); if (it != neighbours.end()) {

问题 I have a shapefile of world countries, downloaded from here. I can plot it in R using countries <- readOGR("shp","TM_WORLD_BORDERS-0.3",encoding="UTF-8",stringsAsFactors=F) par(mar=c(0,0,0,0),bg=rgb(0.3,0.4,1)) plot(countries,col=rgb(1,0.8,0.4)) Now I wanna plot it in orthographic projection (Earth seen from outer space), so I'm trying countries <- spTransform(countries,CRS("+proj=ortho +lat_0=-10 +lon_0=-60")) I also played with the x_0 and y_0 parameters (as stated here), but I always get

问题 I'm trying to dynamically add elements to a vector that is contained within a map, to store multiple arrays of "Particle" objects that are mapped to different ids. I'm new to the language and so I'm having trouble understanding if this can only be done with iterators? In this case it feels like overkill. Is it possible to directly access a vector inside a map? Since I can access the map elements by key, and because there is only one vector per key, it seems like it should be possible. I don't

问题 Last I checked Google and Yahoo do NOT allow you to put their maps behind a login for a commercial application. Not sure about Microsoft. The only other option that I know of is OpenStreeMaps, which I assume is free. OpenStreetMaps says to use one of these third party APIs OpenLayers, Mapstraction, Staticmaps or CloudMade's Web Maps Lite for their maps did I miss anyone? So my question to be more specific is: In terms of price, quality, performance and ease of implementation which one is best