hashtable

Possible Duplicate: How to sort a Map<Key, Value> on the values in Java? I have a HashMap of the type: HashMap<String, Integer> h = new HashMap<String, Integer>(); The HashMap contains a list of Strings and the Integer is a counter for the number of times that String has been found. What I would like to be able to do is sort the HashMap based on the Integers, then on the alphabetical order of the Strings. At the moment I am keeping a record of the largest occurrence of a word (variable named max) and displaying the values as follows: public void print(){ while(max > 0){ for (String key : h

I pretty don't understand why this test : http://jsperf.com/push-method-vs-setting-via-key Shows that a.push(Math.random()); is over ten times slower than a[i] = Math.random(); Could you explain why this is the case ? What magic "push" do that make it so slow ? (or so slow compared to other valid method of doing that). EDIT NOTE: The push test is biased. I increase size of the array every iteration! Read carefully accepted answer! Bergi Could you explain why this is the case? Because your test is flawed. The push does always append to the existing a array making it much larger, while the

Dictionary key requires Hashable conformance: class Test {} var dictionary = [Test: String]() // Type 'Test' dies not conform to protocol 'Hashable' class Test: NSObject {} var dictionary = [Test: String]() // Works How to get address of pure Swift class instance to use as hashValue ? Martin R For Swift 3 (Xcode 8 beta 6 or later), use ObjectIdentifier . class Test : Hashable { // Swift 2: var hashValue: Int { return unsafeAddressOf(self).hashValue } // Swift 3: var hashValue: Int { return ObjectIdentifier(self).hashValue } } func ==(lhs: Test, rhs: Test) -> Bool { return lhs === rhs } Then a

Is there a way to keep the order of keys in a hashtable as they were added? Like a push/pop mechanism. Example: $hashtable = @{} $hashtable.Add("Switzerland", "Bern") $hashtable.Add("Spain", "Madrid") $hashtable.Add("Italy", "Rome") $hashtable.Add("Germany", "Berlin") $hashtable I want to retain the order in which I've added the elements to the hashtable. Loïc MICHEL There is no built-in solution in PowerShell V1 / V2. You will want to use the .NET System.Collections.Specialized.OrderedDictionary : $order = New-Object System.Collections.Specialized.OrderedDictionary $order.Add("Switzerland",

how to convert a HashTable to Dictionary in C#? is it possible? for example if I have collection of objects in HashTable and if I want to convert it to a dictionary of objects with a specific type, how to do that? public static Dictionary<K,V> HashtableToDictionary<K,V> (Hashtable table) { return table .Cast<DictionaryEntry> () .ToDictionary (kvp => (K)kvp.Key, kvp => (V)kvp.Value); } var table = new Hashtable(); table.Add(1, "a"); table.Add(2, "b"); table.Add(3, "c"); var dict = table.Cast<DictionaryEntry>().ToDictionary(d => d.Key, d => d.Value); also you can create an extension method for

In Java, if I create a Hashtable<K, V> and put N elements in it, how much memory will it occupy? If it's implementation dependent, what would be a good "guess"? Edit; Oh geez, I'm an idiot, I gave info for HashMap, not HashTable. However, after checking, the implementations are identical for memory purposes. This is dependent on your VM's internal memory setup (packing of items, 32 bit or 64 bit pointers, and word alignment/size) and is not specified by java. Basic info on estimating memory use can be found here . You can estimate it like so: On 32-bit VMs, a pointer is 4 bytes, on 64-bit VMs,