hashtable

问题 I have a Hash Table like, HashTable ht = { (1, 1), (2, 1), (3, 1) } Now, I implement it like, Integer foo = Integer(1) and declare hash table like, HashTable ht = { (foo, foo), (2, foo), (3, foo) } Now, as per I understood from this, it will reduce heap space used by JVM. Is this correct ? Another point is that, in C, I usually use structure like, HashTable ht = { (1, mem), (2, mem), (3, mem) } { where mem is memory location (say 10) of 1 } And then use the location to access the value. Now,

问题 I was wondering if you knew of a robust implementation of a hashtable in C. I'm looking for something other than ghashtable in glib. Thanks. 回答1: I've heard good things about the GLib Hash Table. 回答2: Will this hashtable work? (got the link from the second post of this thread) Perhaps this one will? (got the above from a Google search for "hashtable in c", am not a C programmer) 回答3: For a hash table I'd use google-sparsehash PD: I don't know your requirements, but take a look at HDF5, bear

问题 Now, I'm trying to understand how to construct the Hashtable . The most interesting - as objects are added to the Hashtable ? I have read in a book that: at first step: Calculated hashCode() object. Next, we determine the position of this object in the Hashtable : obj.hashCode() % Hashtable.length . For example, add more elements to the Hashtable : Hashtable<String, String> hm=new Hashtable<String, String>(100); hm.put("Lee","Lee"); hm.put("lee","lee"); hm.put("eel","eel"); Define a bucket

问题 I am struggling to find a neat way to turn a delimited string into a hashtable. For example given the string: UK_Kent_Margate I want to turn this into a PowerShell HashTable that looks like this: $result = @{ UK = @{ Kent = @{ Margate = @{} } } } So I can easily break the string into an array using a split on the '_' character but then I am struggling (read stuck!) with testing and declaring each of the nested hashes in the results hash. I think I will need a recursive function which is no

问题 Why is the table field of Hashtable serialized, although it is marked as transient ? 回答1: It is marked as transient because it is unsafe to use the default serialization scheme on the Entry array. Rather, when a Hashtable is deserialized, the keys in the table must be rehashed and the entries must be added to slots according to the new hashcode values. This is necessary because the keys may have different hashcodes after deserialization ... for a variety of reasons. This work will be done by

问题 I have a file .txt with 3 columns: ID-polygon-1, ID-polygon-2 and distance. When I import my file into Netlogo, I obtain 3 lists [[list1][list2][list3]] which corresponds with the 3 columns. I used table:from-list list to create a table with the content of 3 lists. I obtain {{table: [[1 1] [67 518] [815 127]]}} (The table displays the first two lines of my dataset). For example, I would like to get the value of distance (list3) between ID-polygon-1 = 1 (list1) and ID-polygon-2 = 67 (list1),

问题 I am trying to implement HashTable in C++ via templates. Here is the signature: template<class T1, class T2> class HashTable { public: void add(T1 a, T2 b); void hashFunction(T1 key, T2 value) { // how to implement this function using key as a generic // we need to know the object type of key } }; So, I am unable to move ahead with implementation involving a generic key. In Java, I could have easily cast the key to string and then be happy with implementing the hash for a key as string. But,

问题 I am trying to get the count of the most repeated letter in a word function GreatestCount(str) { var count = {} for (var i = 0 ; i<str.length;i++) { var char = str[i]; count[char] = (count[char] || 0) + 1; } //get the largest number for the letter counts var max = 0; for (var c in count) { if (count[c] > max) max = count[c]; } return max } can someone explain to me why count[char] = (count[char] || 0) + 1;// this works count[char] += 1 // this does not work 回答1: Because count[char] += 1 is

问题 I fetch multiple records with the same id and I want to store them in a Hashtable in C#. I'm using the id as the key in the Hashtable , and the value is the object itself. It throws an exception because the same key is added again. Is there a way to fix this problem? This is my code: Hashtable localItemsIndex = new Hashtable(); foreach (TzThing thing in localThingz) localItemsIndex.Add(thing.Id, thing); Thanks in advance jennie 回答1: Maybe you should use Dictionary<Id,List<TzThing>> to store

问题 This is the set of result from my database print_r($plan); Array ( [0] => Array ( [id] => 2 [subscr_unit] => D [subscr_period] => [subscr_fee] => ) [1] => Array ( [id] => 3 [subscr_unit] => M,Y [subscr_period] => 1,1 [subscr_fee] => 90,1000 ) [2] => Array ( [id] => 32 [subscr_unit] => M,Y [subscr_period] => 1,1 [subscr_fee] => 150,1500 ) ) How can I change the $plan[0] to $plan[value_of_id] Thank You. 回答1: This won't do it in-place, but: $new_plan = array(); foreach ($plan as $item) { $new