I have a collection of book objects in a HashMap. The book has book_title, book_author, book_year_published, etc. I want to sort them based on the book_title which is a String, in both ascending and descending order, and display them on the screen. I wish someone can help me - I have been doing this for hours and still havent come up w...
Having some maps defined as: var valueToSomeType = map[uint8]someType{...} var nameToSomeType = map[string]someType{...} I would want a variable that points to the address of the maps (to don't copy all variable). I tried it using: valueTo := &valueToSomeType nameTo := &nameToSomeType but at using valueTo[number], it shows internal...
I have a string like def data = "session=234567893egshdjchasd&userId=12345673456&timeOut=1800000" I want to convert it to a map ["session", 234567893egshdjchasd] ["userId", 12345673456] ["timeout", 1800000] This is the current way I am doing it, def map = [:] data.splitEachLine("&"){ it.each{ x -> def object = x.s...
I was wondering how Java orders items in the Map (HashMap or Hashtable) when they are added. Are the keys ordered by the hashcode, memory reference or by allocation precedence...? It's because I've noticed same pairs in the Map are not always in the same order ...
This is code to write hashtable to .txt file ! public static void save(String filename, Map<String, String> hashtable) throws IOException { Properties prop = new Properties(); prop.putAll(hashtable); FileOutputStream fos = new FileOutputStream(filename); try { prop.store(fos, prop); } finally { fos.clos...
I can't seem to figure out the syntax for finding structs in containers. I have a multiset of Event structs. I'm trying to find one of these structs by searching on its key. I get the compiler error commented below. struct Event { public: bool operator < ( const Event & rhs ) const { return ( time < rhs.time ); } bool operat...
When I do System.out.println(map) in Java, I get a nice output in stdout. How can I obtain this same string representation of a Map in a variable without meddling with standard output? Something like String mapAsString = Collections.toString(map)? ...
Hi folks! Actually I'm new to C++. I tried something out (actually the map container) but it doesn't work the way I assumed it will... Before posting my code, I will explain it shortly. I created 3 classes: ClassA ClassDerivedA ClassAnotherDerivedA The two last ones are derived from "ClassA". Further I created a map: map<stri...
I want to find out the key for given value from HashMap, currently I have to go through all keys and check its value in map, is there a faster way? ...
Hello, I have constructed a map and loaded it with data. If I iterate over all the elements I see they are all valid. However, the find method doesn't find my item. I'm sure it's something stupid I am doing. Here is snippet: // definitions // I am inserting a person class and using the firstname as the key typedef std::map<char*,Per...
Hi, I'm having a bit of a problem with my Android application. I have 2 activities (among many others) which are Map activities. The problem is that whenever I call the 2nd map activity and if the map view changes from that which was on the 1st map activity, the app crashes when returning to the first. Well not really crash, since it's...
I have homework where I am to update a list using a function that takes two elements and returns a value of part of the first element given in the function. So it's required to update the entire listing by going through each element and update its value by applying the function against all other elements in the list (including itself). ...
G'day guys, Trying currently to finish up a bit of homework I'm working on, and having an issue where I'm trying to apply map across a function that accepts multiple inputs. so in the case I'm using processList f (x:xs) = map accelerateList f xs x xs processList is given a floating value (f) and a List that it sorts into another List ...
I'm looking to have JSTL loop through a Map and output the value of the key and it's value. For example I have a Map which can have any number of entries, i'd like to loop through this map using JSTL and output both the key and it's value. I know how to access the value using the key, ${myMap['keystring']}, but how do I access the key?...
Hi, I have a set of points which define a route and I must draw them so a vehicle's moving direction is denoted. The points may be from a curve and I need to draw some arrows. I want to draw arrows on the route to define which arrow vehicle goes. I have a mapviewr java applet and the last I must do is this work, I want to...
Hi guys, I have to implement map values in my Grails app. I have a class that can contain 0..N OsmTags, and the key is unique. In Java I would model this with a Map in each object, but I don't know how to map classes in Grails. So I defined this class: class OsmTag { /** OSM tag name, e.g. natural */ String key /** OSM tag...
I have a map where I'd like to perform a call on every data type object member function. I yet know how to do this on any sequence but, is it possible to do it on an associative container? The closest answer I could find was this: Boost.Bind to access std::map elements in std::for_each. But I cannot use boost in my project so, is there ...
Hi. I'm working on my C++ assignment about soccer and I encountered a problem with map. My problem that I encountered is that when I stored 2 or more "midfielders" as the key, even the cout data shows different, but when I do a multiplication on the 2nd ->second value, it "adds up" the first ->second value and multiply with it. E.g. J...
Given a series of GPS coordinate pairs, I need to calculate the area of a polygon (n-gon). This is relatively small (not larger than 50,000 sqft). The geocodes are created by applying an affine transform with data from a world file. I have tried to use a two step approach by doing converting the geocodes to cartesian coordinates: dou...
I'm a little confused by how keyword accesses seem to behave in Clojure when they are evaluated at macro expansion time. The following works as I expect: (def m {:a 1}) (:a m) => 1 However the same keyword access doesn't seem to work within a macro: (def m {:a 1}) (defmacro get-a [x] (:a x)) (get-a m) => nil Any idea what is goin...