hashtable

问题 We've just encountered this error on our web app, and immediately found the article here Hashtable insert failed. Load factor too high. - ASP.NET 2.0. However, the hotfix that this points to (http://support.microsoft.com/?id=927579) was already included in .NET 2.0 SP1 (http://support.microsoft.com/kb/945757). A restart of the WWW Publishing Service made it go away. Does anyone know of any other valid conditions where this can occur? And how to make sure they don't happen? Thanks. Edit: I

问题 I have two hash tables created from data from two different XML files. What I would like to do is combine the two tables into a single hash table based on a common value in the both tables. Inv Hash: $invHash = $invXML.InventoryDto.ProductInventoryItem.SkuInventoryItem | select @{ L = 'SkuID'; E = { $_.SkuId } }, @{ L = 'SkuStatusCode'; E = { if ($_.SkuStatusCode -eq 'Active') { 'True' } else { 'False'} } }, @{ L = 'QuantityOnHand'; E = { $_.QuantityOnHand } } Sample Contents of $invHash:

问题 I understand there is a hashing technique is applied to a key to store its value in the memory address. But I don't understand how the collision is happening here? Which hashing algorithm does Java use to create a memory space ? Is it MD5? 回答1: The basic idea of HashMap is this: A HashMap is really an array of special objects that hold both Key and Value. The array has some amount of buckets (slots), say 16. The hashing algorithm is provided by the hashCode() method that every object has.

问题 I am well aware of all the problems involved in comparing floats. This is exactly the reason for this question. I'm looking to create a fast hash table for values that are 3D vectors (3 floats - x,y,z). It can be assumed that the length of the vector is always 1.0 ( sqrt(x*x+y*y+z*z) is 1.0) Essentially this means that I'm looking for a hash function that takes values that are almost equal to the same unsigned int value and a corresponding equality operator that is true if the hash values are

问题 What's the big O for JavaScript's array access when used as a hash? For example, var x= []; for(var i=0; i<100000; i++){ x[i.toString()+'a'] = 123; // using string to illustrate x[alpha] } alert(x['9999a']); // linear search? One can hope JS engines will not use a linear search internally O(n), but is this for sure? 回答1: Accessing object properties and array elements in JavaScript is syntacticly assumed to be done in constant time: O(1). Performance characteristics are not guaranteed in the

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . I have a few questions on a data-structure called a hash table (also know as associative array) and how it is implemented in C. How do you make a hash table in C? What is a hashtable and how do you implement it? Why would I want to use a hash table rather than an array? NOTE: I

问题 I'm building a symbol table for a project I'm working on. I was wondering what peoples opinions are on the advantages and disadvantages of the various methods available for storing and creating a symbol table. I've done a fair bit of searching and the most commonly recommended are binary trees or linked lists or hash tables. What are the advantages and or disadvantages of all of the above? (working in c++) 回答1: Your use case is presumably going to be "insert the data once (e.g., application

问题 I usually use C++ stdlib map whenever I need to store some data associated with a specific type of value (a key value - e.g. a string or other object). The stdlib map implementation is based on trees which provides better performance (O(log n)) than the standard array or stdlib vector. My questions is, do you know of any C++ "standard" hashtable implementation that provides even better performance (O(1))? Something similar to what is available in the Hashtable class from the Java API. 回答1: If

问题 I've done a little research on hash tables, and I keep running across the rule of thumb that when there are a certain number of entries (either max or via a load factor like 75%) the hash table should be expanded. Almost always, the recommendation is to double (or double plus 1, i.e., 2n+1) the size of the hash table. However, I haven't been able to find a good reason for this. Why double the size, rather than, say, increasing it 25%, or increasing it to the size of the next prime number, or

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . I need to map primitive keys (int, maybe long) to struct values in a high-performance hash map data structure. My program will have a few hundred of these maps, and each map will generally have at most a few thousand entries. However, the maps will be "refreshing" or "churning" constantly; imagine processing