What’s a correct and good way to implement __hash__()? I am talking about the function that returns a hashcode that is then used to insert objects into hashtables aka dictionaries. As __hash__() returns an integer and is used for “binning” objects into hashtables I assume that the values of the returned integer should be uniformly … Read more
One of the basic data structures in Python is the dictionary, which allows one to record “keys” for looking up “values” of any type. Is this implemented internally as a hash table? If not, what is it? 4 Answers 4
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. … Read more
If I pass the same key multiple times to HashMap’s put method, what happens to the original value? And what if even the value repeats? I didn’t find any documentation on this. Case 1: Overwritten values for a key Map mymap = new HashMap(); mymap.put(“1″,”one”); mymap.put(“1″,”not one”); mymap.put(“1″,”surely not one”); System.out.println(mymap.get(“1”)); We get surely not … Read more
I’m looking for an explanation of how a hash table works – in plain English for a simpleton like me! For example, I know it takes the key, calculates the hash (I am looking for an explanation how) and then performs some kind of modulo to work out where it lies in the array where … Read more
I need to store some statistics using JavaScript in a way like I’d do it in C#: Dictionary<string, int> statistics; statistics[“Foo”] = 10; statistics[“Goo”] = statistics[“Goo”] + 1; statistics.Add(“Zoo”, 1); Is there an Hashtable or something like Dictionary<TKey, TValue> in JavaScript? How could I store values in such a way? 1Best Answer 11 Use JavaScript … Read more
What is the equivalent of Python dictionaries but in Bash (should work across OS X and Linux). 15 s 15 Bash 4 Bash 4 natively supports this feature. Make sure your script’s hashbang is #!/usr/bin/env bash or #!/bin/bash so you don’t end up using sh. Make sure you’re either executing your script directly, or execute … Read more
What are the differences between a HashMap and a Hashtable in Java? Which is more efficient for non-threaded applications? 3 35
Usually hashes wouldn’t do sums, otherwise stop and pots will have the same hash. and you wouldn’t limit it to the first n characters because otherwise house and houses would have the same hash. Generally hashs take values and multiply it by a prime number (makes it more likely to generate unique hashes) So you … Read more
