Description | A Java program to read a text file and print each of the unique words in alphabetical order together with the number of times the word occurs in the text. The program should declare a variable of type Map<String, Integer> to store the words and corresponding frequency of occurrence. Which concrete type, though? TreeMap<St...
I have the following code, which splits up a Vector into a string vector (to use as a key) and an integer at the end (to use as value). payoffs.put(new Vector<String>(keyAndOutput.subList(0, keyAndOutput.size() - 1)), Integer.parseInt(keyAndOutput.lastElement())); The TreeMap in question is constructed using a Comparator with the foll...
Most places I've consulted say to use SortedList, but the problem is that the program I'm porting actually uses duplicate keys (differentiated by order), which is permissible with TreeMap, but not SortedList. Any advice? ...
Is it possible to extract the top n (I use top because I believe a TreeMap is sorted) key elements from a TreeMap, without iterating using an Iterator object. I can do the iteration but it's tedious to have to check for nulls etc. ...
I want to have a List or Array of some sort, storing this information about each country: 2 letter code Country name such as Brazil Continent/region of the world such as Eastern Europe, North America, etc. I will classify each country into the region/continent manually (but if there exists a way to do this automatically, do let me k...
Are there any frameworks for building squarified treemaps in C# 2.0 WinForms? Something similar to this: (from http://www.codeproject.com/KB/recipes/treemaps.aspx) ...
I'm developing a 'TreeDict' class in Python. This is a basically a dict that allows you to retrieve its key-value pairs in sorted order, just like the Treemap collection class in Java. I've implemented some functionality based on the way unique indexes in relational databases can be used, e.g. functions to let you retrieve values corre...
What I'm trying I'm trying to use java.util.TreeMap in a J2ME application. I know that TreeMap is present on J2SE but not on J2ME, so I've made some efforts to port the J2SE 6.0 TreeMap to J2ME 1.2 and included it in my Midlet Jar. This involved porting half of the collections framework, but now I'm (theoretically) done with that and wa...
I want to iterate over a treeMap, and for all 'key's which have a particular value, I want them to be added to a new TreeMap. How can i do this? Code samples would be prefered. ...
I have a list of objects I need to sort according to properties of one of their fields. I've heard that SortedMap and Comparators are the best way to do this. Do I implement Comparable with the class I'm sorting, or do I create a new class? How do I instantiate the SortedMap and pass in the Comparator? How does the sorting work? Will i...
How can I sort a treemap using its values rather than the key? ...
I have a TreeMap that maps String keys to a custom City class. Here is how it is instantiated: TreeMap<String, City> nameDictionary = new TreeMap<String, City>(new CityNameComparator()); CityNameComparator implementation: public class CityNameComparator implements Comparator<String> { public int compare (String c1, String c2...
Is there a way to prevent a treemap from accepting null values, or do I need to do a check every time I enter something? ...
Well, I tested TreeMap but it doesn't take in account IgnoreCase on string comparision. I need to order lexicographically and ignoring case. Is there any other way? Thanks, that works (TreeMap (Comparator c)). However, I have another question: public final Comparator<Object> STR_IGN_CASE_COMP = new Comparator<Object>() { public in...
This is where I'm at: public final Comparator<Object> ID_IGN_CASE_COMP = new Comparator<Object>() { public int compare(Object o1, Object o2) { String s1 = null; String s2 = null; try { Class c = o1.getClass(); IO.println(c.getName()); //java.lang.string instead of Animal M...
public final Comparator<String> ID_IGN_CASE_COMP = new Comparator<String>() { public int compare(String s1, String s2) { return s1.compareToIgnoreCase(s2); } }; private Map< String, Animal > _animals = new TreeMap< String, Animal >(ID_IGN_CASE_COMP); My problem is, how to use method get(id) ignoring th...
I have a Map[Long, String] which I would like iterate over in descending order of the keys. The way I chose to do this was as follows: var m: SortedMap[Long, String] = TreeMap.empty( (l: Long) => -l) m ++= Map(2L -> "Hello", 1L -> "World", 3L -> "Chris") println(m) //Map(3 -> Chris, 1 -> World, 2 -> Hello) I'm really not sure I unders...
I'm writing a Java program that's using the TreeMap interface, and I'm having a problem with containsKey. It is returning true even when I give containsKey something that I know for certain is not in the TreeMap. What could be the cause of this? Thanks so much in advance. -- Edit: I am writing a program that counts the occurrences o...
I'm developing a Java application and am new to using TreeMap. The program needs to keep track of the number of occurrences of each word in a text file. However, I'm having trouble putting my data into the TreeMap. It works fine when I use the same exact code to put the data into a HashMap, but I need the data to be sorted by the value....
How can one calculate how much memory a Java TreeMap needs to handle each mapping? I am doing an experiment with 128 threads, each dumping 2^17 longs in its own array. All these 2^24 longs are then mapped to ints (TreeMap<Long,Integer>), each array reference is nulled before moving to the next. That should amount to 128+64 MB for the ...