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Here's Pair.java
import java.lang.*; import java.util.*; public class Pair<TYPEA, TYPEB> implements Comparable< Pair<TYPEA, TYPEB> > { protected final TYPEA Key_; protected final TYPEB Value_; public Pair(TYPEA key, TYPEB value) { Key...
Started by Chris Kaminski on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
Totally different method that never gets) { System.out.println("in equals()"); if (o instanceof Pair) { Pair<?, ?> p1 = (Pair<?, ?>) o not print "in equals()" after "....
The method with an additional version that takes a Pair .
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So I need a 2-dimensional ConcurrentHashMap .
It has to be as blazing fast as possible, as I'm going to be adding to and updating its values extremely frequently. It's in a multithreaded application, hence the choice to use ConcurrentHashMap instead of...
Started by DanM on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
*/ void recordAccess....
However it will need); } public final String toString() { return "[" + x + ", " + y + "]=" + value; } /** * This method that's already in the HashMap.
I find it is faster than using an IntPair as key .
Java HashMap.
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I understand that the String class' hashCode() method is not guarantied to generate unique hash codes for distinct String-s. I see a lot of usage of putting String keys into HashMap-s (using the default String hashCode() method). A lot of this usage could...
Started by Marcus on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
You are talking about hash one would expect that the String.equals method will also be called to be sure that the String s are truly equal, if there is indeed....
No, it would not be a bad idea to use a String for a key to a HashMap .
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Hi
I am developing a parser that needs to put key value pairs in hashmap.
But a key can have multiple values which i can do in this way
HashMap<String,ArrayList<String>> .
But what happens if number of keys are very large and it start matching...
Started by changed on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
HashMap is collision-safe: look at the sourcecode for put:
/** * Associates the specified value.
Hash codes are not guaranteed or required to be unique; HashMap maintains.
Hashcode will not collide.
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I am wondering what is the memory overhead of java HashMap compared to ArrayList?
Update:
I would like to improve the speed for searching for specific values of a big pack (6 Millions+) of identical objects.
Thus, I am thinking about using one or several...
Started by elhoim on
, 12 posts
by 12 people.
Answer Snippets (Read the full thread at stackoverflow):
A map (such as HashMap: based on your comment, I ....
As Jon Skeet noted, these are completely different structures.
There are different instances where you'll need a key/value pair (where you may use a HashMap ) and different nice.
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As made clear in update 3 on this answer , this notation:
var hash = {}; hash[X]
does not actually hash the object X ; it actually just converts X to a string (via .toString() if it's an object, or some other built-in conversions for various primitive...
Started by Claudiu on
, 8 posts
by 8 people.
Answer Snippets (Read the full thread at stackoverflow):
If you were to....
You'd have to store in some internal state couplets of object/value pairs
HashMap = {}; // unique object instance var shape = {}; // unique object instance var map = new HashMap(); map.put(color.
Or DojoX UUID.
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My problem is actually more nuanced than the question suggests, but wanted to keep the header brief.
I have a HashMap<String, File> of File objects as values. The keys are String name fields which are part of the File instances. I need to iterate...
Started by milkplusvellocet on
, 10 posts
by 10 people.
Answer Snippets (Read the full thread at stackoverflow):
If you get in the....
Sort it with Collections.sort() according to your hashmap...
You have a temporary List, then add each pair of data into it.
Unfortunately there is no way of getting data out of a HashMap in any recognizable order.
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Hi all,
I'm having some trouble looping over a HashMap to print out it's values to the screen. Could someone double check my code to see what I'm doing wrong. I can't seem to find anything wrong but there must be something.
In a servlet, I am adding the...
Started by Lee Theobald on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
To:
${item} ${item.key} ${item.item}
If you change "discipline" to be of type List<Map.Entry<String create your list like so:
Map<String, String> facetValues = new HashMap<String, String>(); // Filling the map List....
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Hi! I have a question.
I have a list of names, say 8 names: Joe, Bob, Andrew, Bill, Charlie, Sarah, Ann, Victor
The count of names might differ**.
1) What should I use as name list? Hashmap, Vector, Hashtable, List, ArrayList?
2) I need to match them ...
Started by Andrey on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
You can pair names this way:
String input = "Joe, Bob, Andrew, Bill, Charlie, Sarah, Ann, Victor"; String names[] = input.split(","); Map<String....
Also you don't say whether the names are unique.
You need to do with them.
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I have a HashMap with millions of entries.
Need to retrieve all entries whose keys match a specific set of criteria (in this case, each key is an object with two integer properties; I need to retrieve all keys where each of these integers fall within ...
Started by DanM on
, 8 posts
by 8 people.
Answer Snippets (Read the full thread at stackoverflow):
A HashMap is not an efficient data structure for finding keys that lie within a certain main(String[] args) { Comparator<Foo> fooComparator = new Comparator<Foo>() { @Override; j) return i; else return j; } @Override....
Together.
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