linkedhashmap

How is the internal implementation of LinkedHashMap different from HashMap implementation?

由 怎甘沉沦 提交于 2019-11-27 09:47:11
问题 I read that HashMap has the following implementation: main array ↓ [Entry] → Entry → Entry ← linked-list implementation [Entry] [Entry] → Entry [Entry] [null ] So, it has an array of Entry objects. Questions: I was wondering how can an index of this array store multiple Entry objects in case of same hashCode but different objects. How is this different from LinkedHashMap implementation? Its doubly linked list implementation of map but does it maintain an array like the above and how does it

How get value from LinkedHashMap based on index not on key? [duplicate]

由 こ雲淡風輕ζ 提交于 2019-11-27 07:33:27
This question already has an answer here: How to get position of key/value in LinkedHashMap using its key 4 answers I have LinkedHashMap<String, List<String>> hMap; I want to get List<String> by position not on key. I don't want to use iterate. Is there any other way to get Value based on index ? PermGenError You can't get the value of the Map based on index, Map s just don't work that way. A workaround would be to create a new list from your values and get the value based on index. LinkedHashMap<String, List<String>> hMap; List<List<String>> l = new ArrayList<List<String>>(hMap.values()); l

Casting LinkedHashMap to Complex Object

由 前提是你 提交于 2019-11-27 06:40:01
I've got an application that stores some data in DynamoDB using Jackson to marshall my complex object into a JSON. For example the object I'm marshalling might look like this: private String aString; private List<SomeObject> someObjectList; Where SomeObject might look like this: private int anInteger; private SomeOtherObject; and SomeOtherObject might look like this: private long aLong; private float aFloat; This is fine an the object gets marshalled no problem and stored in the DB as a JSON string. When it comes time to retrieve the data from DynamoDB Jackson automatically retrieves the JSON

Java : Cartesian Product of a List of Lists

由 一笑奈何 提交于 2019-11-27 04:21:09
问题 I have a problem that is really kind of a general programming question, but my implementation is in Java, so I will provide my examples that way I have a class like this: public class Foo { LinkedHashMap<String, Vector<String>> dataStructure; public Foo(LinkedHashMap<String, Vector<String>> dataStructure){ this.dataStructure = dataStructure; } public String[][] allUniqueCombinations(){ //this is what I need to do } } I need to generate a nested array from my LinkedHashMap that represents

How to add element at specific index/position in LinkedHashMap?

由 风流意气都作罢 提交于 2019-11-27 02:29:38
问题 I have an ordered LinkedHashMap and i want to add element at specific index , say at first place or last place in the map. How can i add element in LinkedHashMap at an specific position? Even if I could add an element to FIRST or LAST position in LinkedHashMap would help! 回答1: You can not change the order. It is insert-order (by default) or access-order with this constructor: public LinkedHashMap(int initialCapacity, float loadFactor, boolean accessOrder) Constructs an empty LinkedHashMap

LinkedHashMap in .NET

由 牧云@^-^@ 提交于 2019-11-27 02:04:11
I wonder if there is a counterpart to java.util.LinkedHashMap in .NET? (ie. the elements are (re)ordered automatically if I access an element. (boolean accessOrder) ). A bit of Googling seems to show that there is no built in C# equivalent for LinkedHashMap, but there are some third party options available. Just to clarify a bit for readers: LinkedHashMap only behaves that way when built with one particular constructor overload. Normally the elements are maintained in insert order. (This feels a little odd to me, but never mind.) I don't believe there's any such class in .NET. It wouldn't be

Does Java's LinkedHashMap maintain the order of keys? [duplicate]

由 人走茶凉 提交于 2019-11-27 02:02:32
问题 This question already has answers here : Is the order guaranteed for the return of keys and values from a LinkedHashMap object? (7 answers) Closed 4 years ago . When LinkedHashMap.keySet() is called, will the order of the Set returned be the same as the order the keys were added in? 回答1: Yes. See: LinkedHashMap: This linked list defines the iteration ordering, which is normally the order in which keys were inserted into the map (insertion-order). and from the HashMap#keySet documentation: The

How to get position of key/value in LinkedHashMap using its key

由 被刻印的时光 ゝ 提交于 2019-11-27 01:35:09
问题 Hi I have a LinkedHashMap (called info) that contains name/age (string/int) pairs. I want to find out, how can I get the position of the key/value if i input the key. For example, if my LinkedHashMap looked like this {bob=12, jeremy=42, carly=21} and I was to search jeremy, it should return 1 as its in position 1. I was hoping I can use something like info.getIndex("jeremy") 回答1: HashMap implementations in general are un-ordered for Iteration . LinkedHashMap is predictablely ordered for

What is the difference between LRU and LFU

由 こ雲淡風輕ζ 提交于 2019-11-27 00:01:49
问题 What is the difference between LRU and LFU cache implementations? I know that LRU can be implemented using LinkedHashMap . But how to implement LFU cache? 回答1: Let's consider a constant stream of cache requests with a cache capacity of 3, see below: A, B, C, A, A, A, A, A, A, A, A, A, A, A, B, C, D If we just consider a Least Recently Used (LRU) cache with a HashMap + doubly linked list implementation with O(1) eviction time and O(1) load time, we would have the following elements cached

Sending LinkedHashMap to intent

由 两盒软妹~` 提交于 2019-11-26 22:07:35
问题 I want send LinkedHashMap to another Intent. But I don't known what method for extras is allowable. Bundle extras = getIntent().getExtras(); LinkedHashMap<Integer, String[]> listItems = extras.get(LIST_TXT); 回答1: You cannot reliably send a LinkedHashMap as an Intent extra. When you call putExtra() with a LinkedHashMap , Android sees that the object implements the Map interface, so it serializes the name/value pairs into the extras Bundle in the Intent . When you want to extract it on the
订阅 linkedhashmap