comparator

read text file and store in hashmap. Then sort in order

由 喜夏-厌秋 提交于 2019-12-04 20:43:24
File is like this: name1 134.2 name2 456.7 name3 265.3 ... ... I read the text file and store in HashMap after that I want to sort in order(by the highest value) but the problem is that because I sort the values in String, I cant compare it. So..is there a way to put the values of textfile into hashmap in double or integer form? import java.io.*; import java.util.*; class Test { public static void main(String[] args) throws FileNotFoundException { Scanner scanner = new Scanner(new FileReader("score.txt")); HashMap<String, String> map = new HashMap<String, String>(); while (scanner.hasNextLine(

Priority queue with Pointers and Comparator C++

由 跟風遠走 提交于 2019-12-04 12:24:53
问题 I just started to learn C++, Half of the time I don't know what am I doing, spend hours and hours searching on Google and blindly put codes inside my project, this might be a basic question, but I just can't seems to get it right. This is the requirement of my assignment, I need to have these: in the Edge class: public: bool operator()(Edge*, Edge*) in the Graph class: private: priority_queue<Edge*, vector<Edge*>, Edge> edges I have problem declaring the priority_queue. Details: If I directly

C++ string sort like a human being?

由 烂漫一生 提交于 2019-12-04 10:40:34
问题 I would like to sort alphanumeric strings the way a human being would sort them. I.e., "A2" comes before "A10", and "a" certainly comes before "Z"! Is there any way to do with without writing a mini-parser? Ideally it would also put "A1B1" before "A1B10". I see the question "Natural (human alpha-numeric) sort in Microsoft SQL 2005" with a possible answer, but it uses various library functions, as does "Sorting Strings for Humans with IComparer". Below is a test case that currently fails:

Very big JTable, RowFilter and extra load

由 老子叫甜甜 提交于 2019-12-04 05:15:18
问题 I wanted to ask for a clarification about the use of RowFilter and its effects on performances. I implemented a filter through the method include(Entry) that for every row simply checks if its correspondent value in the model has a boolean flag set: if so, returns true, else false. Now, the JTable I have can be pretty big (1000000+ rows), and I wasn't sure if this simple filtering, applied to such a big input set, could be costly. How does the mapping between filtered rows and underlying data

Sorting ArrayList of Arraylist<String> in java

由 孤街浪徒 提交于 2019-12-04 03:40:44
问题 I have an ArrayList of ArrayList of String. In Outer ArrayList on each index each Inner ArrayList has four items have four parameters. Contacts Id Contacts Name Contacts Adress Contacts Number Now I want to sort the complete ArrayList of the on the basis of Contact Name Parameter. Means I want to access the outer Arraylist and the inner ArrayList present on each index of outer Arraylist should be sorted according to contact Name. Comparator / Comparable Interfaces not likely to help me.

TreeSet constructor with Comparator<?> parameter

由 …衆ロ難τιáo~ 提交于 2019-12-03 23:29:50
问题 In Java’s documentation for its class TreeSet one of the constructors is shown to have the following header: TreeSet(Comparator<? super E> c) Can someone help explain why there is a constructor for TreeSet which takes a comparator object as its argument? I have no clue why this is done. 回答1: The elements in a TreeSet are kept sorted. If you use a constructor that has no Comparator, the natural ordering of the element class (defined by the implementation of Comparable ) would be used to sort

Java FX table column sorting with Comparator does not work

由 |▌冷眼眸甩不掉的悲伤 提交于 2019-12-03 22:01:52
In Java FX I would like to display this Model in a sorted TableView: public class ProfilZuordnungTableRowModel { private int id; private double kundenwert; private String kundenwertFormatted; private BooleanProperty selected; } I would like to integrate a table column sorting with the column "Kundenwert". The displayed value should be the attribute "kundenwertFormatted" (String) and for sorting the attribute "kundenwert" (Double) should be used. So I wrote a comparator: class ProfilZuordnungTableRowModelComparator implements Comparator<ProfilZuordnungTableRowModel> { @Override public int

How to compare strings in golang? [closed]

由 风格不统一 提交于 2019-12-03 22:01:10
Closed. This question is off-topic. It is not currently accepting answers. Learn more . Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed last year . I want to make a function that calculates the length of the common segment (starting from the beginning) in two strings. For example: foo:="Makan" bar:="Makon" The result should be 3. foo:="Indah" bar:="Ihkasyandehlo" The result should be 1. peterSO It's not clear what you are asking because you limited your test cases to ASCII characters. I've added a Unicode test case and I've included answers for

Why can a lambda expression be used as a Comparator?

由 南笙酒味 提交于 2019-12-03 19:58:20
问题 In the book OCP Study Guide there is this example about a Comparator that can be initialized in two ways. The first is via an anonymous class like this: Comparator<Duck> byWeight = new Comparator<Duck>(){ public int compare(Duck d1, Duck d2){ return d1.getWeight() - d2.getWeight(); } }; This I can understand. According to the book this can be replaced with a lambda expression like this: Comparator<Duck> byWeight = (d1,d2) -> d1.getWeight() - d2.getWeight(); Now this I don't understand. The

Guava: How to create an explicit Ordering from a List and a single element?

由 主宰稳场 提交于 2019-12-03 16:42:54
问题 In Guava, given a Collection<E> and an element e of type E that I know is in the collection, I'd like to create a custom Ordering<E> that sorts e first and then the rest of the collection. However, the way to get there seems awfully complicated: Collection<String> values = ImmutableList.of("apples", "oranges", "pears"); String first = "oranges"; List<String> remainingValues = newArrayList(values); // this remainingValues.remove(first); // seems Ordering<String> myOrdering = // very Ordering
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