hashmap

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 3 years ago . I've been looking over the internet but I cant seem to find this answer. I have a hashmap: public Map<String, Integer> killstreaks = new HashMap<String, Integer>(); Now I want to call the second value, the integer. SO by using the string as a reference, I know I can do this: killstreaks.get(//idk)

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . I have hashmap and its keys are like "folder/1.txt,folder/2.txt,folder/3.txt" and value has these text files data. Now i am stucked. I want to sort this list. But it does not let me do it :( Here is my hashmap

问题 I am trying to code to read info from a text file, I need to find out how many times each word separated by white space occurs. I then need to output in alphabetical order with the count of each word. I am looking to use a TreeMap, keySet() and an Iterator. My code is very incomplete and I am quite stuck. import java.util.HashMap; import java.util.Map public class WordCount<E extends Comparable<E>> { private static Map<String, Integer> map = new HashMap<String, Integer>(); static { fillMap

问题 This question already has answers here : Sort a Map<Key, Value> by values (54 answers) How to sort Map values by key in Java? (14 answers) Closed 10 months ago . Sort a Map by Key or by value in java Input Map 1-eee 4-ddd 5-ccc 0-bbb 3-aaa 1st Output Map(By-Key): 0-bbb 1-eee 3-aaa 4-ddd 5-ccc 2nd Output Map(By-Value): 3-aaa 0-bbb 5-ccc 4-ddd 1-eee 回答1: This code will first sort the map by Key and then by value. Just write a main method and call this method as follow: import java.util

问题 I have a class Student and Marks. I am using Student Object as Key for HashMap and Marks as Value. If I don't override hashMap and equals, It still works fine. i. Can someone please explain how does it internally works on it if not overriding both equals() and hashcode() ii. what If I override only hashcode() iii.what If I override only equals() class Student { String name; public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; }

问题 I wrote a class that overrides the equals(Object) method in class Object to compare objects of the class type to other objects of a class type using the object's instance values. When I put an instance of the object in a HashMap as the key, and then call get(Object) on the map with a new but identical object as the key, it returns null. I've tried passing a new, identical object to the equals method and it returns true, so the problem isn't my comparison code. From what I've gathered through

问题 This post is very similar to my previous one, but the data structures are different here: Joining an array of keys to a hash with key value pairs like excel vlookup My data from my Mysql2::Result comes back like this array of hashes: data = [{"isbn" => "1234", "title"=>"apple"},{"isbn" => "5678", "title"=>"banana"},{"isbn" => "2121", "title"=>"car"}] And my original list of isbns that I would like to compare is this array: isbns = ["1234","2121", "5454", "5678"] I'm seeking a function which

问题 I currently am using a map in C++ and have a couple of values that are ints and booleans, though the majority of them are strings. I know in Java I could do something like this: std::map<string, Object*> mapvar; but is there an Object equivalent in C++?? If not, is there any way I could properly have values being a std::string , int , or bool ? 回答1: I don't know of a way you could have a std::map with keys that can be multiple types using the stdlib out of the box. Boost has a variant type

问题 So, i have two hashMaps public HashMap<String, Integer> map1 = new HashMap<String,Integer>(); public HashMap<String, Integer> map2 = new HashMap<String,Integer>(); I want to create a hashmap, which consists of both of these hashmaps merged. Also, when I add an element to either of these 2 hashmaps: map1.put("key",1); The third hashmap should have this change SOLUTION: import java.util.*; public final class JoinedMap { static class JoinedMapView<K,V> implements Map<K,V> { private final Map<?

问题 I'm trying to get the data from a text file into a HashMap. The text-file has the following format: it has something like 7 million lines... (size: 700MB) So what I do is: I read each line, then I take the fields in green and concatenate them into a string which will the HashMap key. The Value will be the fild in red. everytime I read a line I have to check in the HashMap if there is already an entry with such key, if so, I just update the value summing the value with the red; If not, a new