I want to store values as key,value,value pair. My data is of type
Key -> int & both values -> ulong, How to initialize & fetch values of such dictionary. I am using VS-2005.
If i use a class or struct then how do i fetch the values.
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9 Answers
Create a structure to store your values:
struct ValuePair { public ulong Value1; public ulong Value2; } Dictionary initialization:
Dictionary<int, ValuePair> dictionary = new Dictionary<int, ValuePair>(); Maybe List is enough, if you use int as key?
List:
List<ValuePair> list = new List<ValuePair>(); ValuePair can be added to the list as following:
list.Add(new ValuePair { Value1 = 1, Value2 = 2 }); 
2 Comments
Nosheen Javed
How will I add the value into the List?
bniwredyc
@NosheenJaved list.Add(new ValuePair { Value1 = 1, Value2 = 2 });
You can declare a class that stores both values and then use an ordinary dictionary. For example:
class Values { ulong Value1 {get;set;} ulong Value2 {get;set;} } var theDictionary=new Dictionary<int, Values>; theDictionary.Add(1, new Values {Value1=2, Value2=3}); 5 Comments
Yann Schwartz
You could make Values a struct instead.
Sune Rievers
Would probably be better to use KeyValuePair instead of a custom class, or at least use a struct.
Daniel Goldberg
A struct could give some space saving and would be more idiomatically correct, but the difference is minor and not so important.
Konamiman
Two ulongs are 16 bytes, so yep, this is one of the rare cases where a struct is appropriate. As for the KeyValuePair, I would'nt use it unless actually the two values are intended to be a key and a value, to make code more understandable.
jayarjo
What does "var theDictionary" syntax mean? Is something like this allowed?
This would be an option:
Dictionary<int, KeyValuePair<ulong, ulong>> dictionary = new Dictionary<int, KeyValuePair<ulong, ulong>>(); If you want to add in a value: Key=1, Pair = {2,3}
dictionary.Add(1, new KeyValuePair<ulong, ulong>(2, 3)); If you want to retrieve those values:
var valuePair = dictionary[1]; ulong value1 = valuePair.Key; ulong value2 = valuePair.Value; Or simply:
ulong value1 = dictionary[1].Key; 
9 Comments
naspinski
I prefer Konamiman's approach as it's cleaner, but this will do without a new class.
Royson
but how do i initialize values to it..give some fetching code also :)
Adriaan Stander
naspinski, that would seem like reinventing the wheel, dont you think?
LukeH
Semantically, a
KeyValuePair consists of a key and a value. The OP wants to store two values, so although a KeyValuePair will do the trick it isn't a great "semantic" fit.naspinski
not really reinventing a wheel, just a different approach - just sticking to base .Net types - Like I said, I would personally go with a new Class, but the OP asked for a Dictionary
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Create a Tuple class, in the System namespace:
public class Tuple<T1,T2> { private readonly T1 _item1; private readonly T2 _item2; public Tuple(T1 item1, T2 item2) { this._item1 = item1; this._item2 = item2; } public T1 Item1 { get { return _item1; } } public T2 Item2 { get { return _item2; } } } And a static Tuple class with a Create method so you get type inference which is not available on constructors:
public static class Tuple { public static Tuple<T1, T2> Create<T1, T2>(T1 item1, T2 item2) { return new Tuple<T1, T2>(item1, item2); } } Then, when you get onto .NET 4.0, you can delete these classes because they're in the Base Class Library (and are compatible with F# tuples!).
Comments
I'm not sure I understand your question correctly, but if you want to store more than one value in the value part of Dictionary, you could do something like this:
var dic = new Dictionary<int,KeyValuePair<ulong,ulong>>(); You can use insert into the dictionary like this:
dic.Add(42, new KeyValuePair<ulong, ulong>(42, 42)); dic.Add(43, new KeyValuePair<ulong, ulong>(43, 43)); And fetch the values like so:
foreach (var a in dic) { Console.WriteLine("Key: {0}, Value1: {1}, Value2: {2}", a.Key, a.Value.Key, a.Value.Value); } 
2 Comments
LukeH
Semantically, a
KeyValuePair consists of a key and a value. The OP wants to store two values, so although a KeyValuePair will do the trick it isn't a great "semantic" fit.Sune Rievers
Right, but I would still prefer this solution to writing a custom struct for this specific task.
In C# 4, you'll have the Tuple type for your value, value pair.
There's an MSDN article describing the type and the design decisions behind it.
Comments
maybe you have to define a class say class Pair to hold your two value, and use int as the key.
Comments
You can make use of the KeyValuePair
Dictionary<int, KeyValuePair<ulong,ulong>> vals = new Dictionary<int, KeyValuePair<ulong, ulong>>(); Comments
Look at Wintellect.PowerCollections Namespace they have special structure Pair<(Of ) and collections to work with it or you'll need to code your own Pair type.
