is there a commonly used data structure for mult-key data? e.g. (key1, key2, ..., keyN) -> value. I used to use dictionaries of dictionaries (in c#), and then wrote my own wrapper on top of this to make the syntax look a bit nicer. but it seems like I still have to write a wrapper for each N-dictionary, where N is the number of keys, sin...
Is it possible to have multiple values for the same key in a hash table? If not, can you suggest any such class or interface which could be used? ...
I've written a game of tic-tac-toe in Java, and my current method of determining the end of the game accounts for the following possible scenarios for the game being over: The board is full, and no winner has yet been declared: Game is a draw. Cross has won. Circle has won. Unfortunately, to do so, it reads through a predefined set o...
I've used HashSet and Dictionary a lot in C#, and found them very fast... I've tried using std::map and std::hash_map and am finding them very slow in comparision. Does this sound like expected behaviour? Is there something I might be doing wrong in my use of std::hash_map? Or, is there a better C++ Hash container out there? I'm has...
I just found out murmur hash, seems to be the fastest known and quite collision resistance. I tried to dig more about the algorithm or implementation in full source code, but I am having difficulty understanding it. Could someone here explain the algorithm used, or implement it in full source code, preferably in C. I read the C source co...
I'd like to store some data in Python in a similar form to a dictionary: {1:'a', 2:'b'}. Every value will be unique, not just among other values, but among keys too. Is there a simple data structure that I can use to get the corresponding object no matter if I ask using the 'key' or the 'value'? For example: >>> a = {1:'a', 2:'b'} >>> ...
I am trying to read a file which contains URLs and are 100 million in number. What I need to do is find out the different websites they are from. So, I am taking chunk of data in memory and reading it line by line. Also, I need to find out how many URLs does each website has in the file and what are those URLs. The way I figured it out i...
Hi, I need to express a collection of about 10-15 short strings (and maybe some ints) as a fairly compact alphanumeric string - one which I can send as a parameter in a get request. Basically, I'm thinking that my collection will be a hashtable, and I'd like to serialize it so it looks sort of like a viewstate string (only hopefully not...
I have a list of string values that I want add to a hashtable or other array that can be accessed by key/index but cannot implement it. I have this working how I want but its ugly List<string> valueList = new List<string>(); valueList.Add("1"); valueList.Add("2"); valueList.Add("3"); Hashtable p ...
I am trying to figure out when and why to use a Dictionary or a HashTable. I have done a bit of a search on here and have found people talking about the generic advantages of the Dictionary which I totally agree with, which leads the boxing and unboxing advantage for a slight performance gain. But I have also read the Dictionary will n...
So I'm reading up about hash tables, hash functions etc. I was intrigued to read on wikipedia about how "dynamic perfect hashing" involves using a second hash table as the data structure to store multiple values within a particular bucket. Where I get lost however, is when it comes to how a universal hash function is selected to perfor...
I am primarily interested in string keys. Can someone point me towards a library? -A ...
I'm interested in techniques people use to publish information and changes to data structures that are being shared across multiple threads without losing much concurrency. In my personal experience I come across the single writer/multiple readers quite often, where a single thread is updating an object, but multiple threads are reading ...
I am using a hashtable to store key-value pairs and I initialize this hashtable (ddl_ht) in the method CreateDropDownLists(). However, when I check the value of "currentItem" in my SelectedIndexChanged method, this value is null. Even though I checked the value of (string)ddl_ht[key[1]] in my Watch window and it shows a value (n...
I need to create a dictionary/hashmap where the Keys are enums Values are some subclass of NSObject NSDictionary won't work here (enums don't conform to NSCopying). I could perhaps use a CFDictionaryRef here, but I'd like to know if is there any other way to achieve this. ...
Hi, I am wondering if anyone can help, I am able to bind to a hash table and display values correctly, yet the two-way binding I have specified doesn't update the object when I make changes. <DataTemplate x:Key="ResponseItemTemplate"> <StackPanel Orientation="Horizontal" > <TextBox Width="200" Text="{Binding Path=...
Possible Duplicate: Can anyone recommend a good Hashtable implementation in Javascript? Hello everyone, I want to calculate/store some statistics information using JavaScript, the equivalent code in C# is below (features I need are -- key-value pair, string/int key value pair, manipulate values by keys, etc.), any ideas how to ...
Am I correct in saying that a .Net Hashtable is not synchronized while a Java Hashtable is? And at the same time a Java HashMap is not synchronized and has better performance? I am rewriting a Java app that makes heavy use of HashMaps in C# and I would like to use a HashTable and ensure that the performance is basically equivalent. ...
This might be a bit of a dumb question, but I'm trying to add some extra key/value pairs to a combo box using VB.NET. The initial item list is generated from a hashtable, which contains a collection of objects. I've managed to add the extra values to the box using the Add method, however I now run into problems when reading back the sel...
Is there any simply way how to create a case insensitive (String -> String) Glib Hash Table? The result should fit this: GHashTable *table; //there should be definition of table g_hash_table_insert(table, "KeY", "Something"); //insert //every command should return the line in table g_hash_table_lookup(table, "Key"); g_hash_table_look...