Is there a elegant way of obtaining only one Entry<K,V> from HashMap, without iterating, if key is not known.
As order of entry of entry is not important, can we say something ... |
I have a List<HashMap<String,Object>> which represents a database where each list record is a database row.
I have 10 columns in my database. There are several rows where the values of 2 ... |
I have been looking for an answer to this and could not find it on SO. So I thought I might share with you all. I want to sort on values, ... |
I have a Java HashMap used to store some basic string values:
Map<String, String> map = new HashMap<String, String>();
map.put("Id", task.getStorageId());
map.put("Name", task.getName());
map.put("Description", task.getDescription());
Under one usage, the Id entry is overwitten by the Description ... |
How to move a particular HashMap entry to Last position?
For Example, I have HashMap values like this:
HashMap<String,Integer> map = new HashMap<String,Integer>();
map= {Not-Specified 1, test 2, testtest 3};
"Not-Specified" may come in any ... |
from p.46 "Effective Java" Joshua Bloch. Item 9: ALways override hashCode when you override equals
- Some class PhoneNumber overrides equals() and doesn't override hashCode()
- "two instances are involved: one is used for insertion ...
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I want to store 100 Million terms and their frequencies (in a text database ) into a HashMap <String, Double>. It is giving me "Out of Memory" Error. I tried to ... |
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If you take a look at the code for HashMap, you'll find empty methods called recordAccess and recordRemoval. What's the purpose of these methods?
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I have a Java HashMap called statusCountMap.
Calling size() results in 30.
But if I count the entries manually, it's 31
This is in one of my TestNG unit tests. These results below are ... |
So the Java WeakHashMap lets one create a map whose entries are removed if its keys become weak. But how can I create a Map whose entries are removed when ... |
I have a hashMap which has the following values as key value(sql date , integer) pairs:
a.put("31-05-2011",67);
a.put("01-06-2011",89);
a.put("10-06-2011",56);
a.put("25-05-2011",34);
when i try to sort the hashMap based on the keys using :
Map modified_a=new TreeMap(a);
and ... |
I've an array of string, I want to find the duplicate strings in the array and want to make the duplicates null by using HashMap with a good time complexity.
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I have a question about HashMaps. We are writing a small-c(-ish) compiler and for that we are using a symbol table. We are implementing this using a hashmap.
Now to take ... |
I need a Map<Integer,String> with a major need to do fast retrievals of values by key. However I also have the need to retrieve List of all entries (key, value pairs) ... |
Hello and good day to you all! I was confused about some Map theory and was hoping someone could help me sort it out. I have been reading the older 1.4 version of Ivor Hortons Beginning Java, and am on the section about HashMaps. Now, he talks about one can get a Set of entries from the HashMap using the entrySet() ... |
Hi, I am inserting entries into a HashMap, but, after iterating through the map, the ordering of the elements inserted into the map are not as were entered. What do I need to do in order to preserve the order ? Do I need to implement the hashCode and equals methods ? Please note that my map's key type is String ... |
Most Map implementations write their data without the entries, as follows: - the number of mappings first - for each mapping, the key first, then the value For instance, if you have a map with contents {key1=value1, key2=value2, key3=value3}, the contents will be written as follows: 3 key1 value1 key2 value2 key3 value3 This is a tad more efficient than writing ... |
I am trying to make a new HashMap from the HashMap entries of the methods. Need to add the entries of a HashMap inside the methods to make a new HashMap. public class Test { private static HashMap mp; public static void main(String[] args) { for (some criteria){ method.invoke() // invoke methods written below one by one } void Method_1(){ mp.put(num1, ... |
Hi, In spite of overriding equals, why HashMap is allowing duplicate entries...? import java.util.HashMap; public class Main { public static void main(String[] args) { HashMap hm = new HashMap(0); hm.put(new Employee(1, "A"), "AA"); System.out.println(hm); hm.put(new Employee(1, "A"), "BB"); System.out.println(hm); } } class Employee { private Integer empId; private String empName; public Employee(Integer i, String n) { this.empId = i; ... |
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//map.put is called for unique database entires only after the condition is met. map.put(id,total); //when I put a print statement here, it gets called 4 times; that means map.put(..) was called four times ! } } // while closes }catch(...) //here the size=1 not 4; it should be 4. return map; } //method closes |