Any such thing as a single column HashTable?

[Joseph Geretz]

Basically, I just need an efficient way to store and retrieve keys from a
list. I don't need key/value pairs. I've implemented this with the standard
HashTable, but the value column is a waste since every key has the same
value, "".

Thanks for your advice.

- Joe Geretz -

 

[Kevin Spencer]

Array of strings?

--
HTH,

Kevin Spencer
Microsoft MVP

Printing Components, Email Components,
Networking Components, Controls, much more.
DSI PrintManager, Miradyne Component Libraries:
http://www.miradyne.net

 

[Jon Skeet [C# MVP]]

Basically, I just need an efficient way to store and retrieve keys from a
list. I don't need key/value pairs. I've implemented this with the standard
HashTable, but the value column is a waste since every key has the same
value, "".

So basically you want a set, right? No, there's nothing built into the
framework. Normally people just use HashTable/Dictionary<K,V> and use
a dummy value.

Jon

 

[Joseph Geretz]

Hi Kevin,

Array of strings?

Will this provide as efficient lookup as the HashTable?

Thanks,

- Joseph Geretz -

 

[Rad [Visual C# MVP]]

Basically, I just need an efficient way to store and retrieve keys from a
list. I don't need key/value pairs. I've implemented this with the standard
HashTable, but the value column is a waste since every key has the same
value, "".

Thanks for your advice.

- Joe Geretz -

An array?

 

[Nicholas Paldino [.NET/C# MVP]]

It might be a little early, but there will be the HashSet class in Orcas
which will introduce this class. Just something to be aware of in the
future.

 

[Jon Skeet [C# MVP]]

It might be a little early, but there will be the HashSet class in Orcas
which will introduce this class. Just something to be aware of in the
future.

Hurrah! Only 5 years after it should have been present

 

[Guest]

I can't wait.
Peter
--
Site: http://www.eggheadcafe.com
UnBlog: http://petesbloggerama.blogspot.com
Short urls & more: http://ittyurl.net

It might be a little early, but there will be the HashSet class in Orcas
which will introduce this class. Just something to be aware of in the
future.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

So basically you want a set, right? No, there's nothing built into the
framework. Normally people just use HashTable/Dictionary<K,V> and use
a dummy value.

Jon

 

[Guest]

How about a StringDictionary?
http://msdn2.microsoft.com/en-us/li...ons.specialized.stringdictionary_members.aspx

It still has that nasty Value member, but its strongly typed and has the
nice convenience lookup methods.
Peter

 

[Joseph Geretz]

Hi Rad,

An array?

Will this provide as efficient lookup as the HashTable?

Thanks,

- Joseph Geretz -

 

[EmeraldShield]

Will this provide as efficient lookup as the HashTable?

No, HashTable is your fastest lookup hands down. Just put an INT in the
data with 0. Then you can just use the keys.

 

[Jon Skeet [C# MVP]]

No, HashTable is your fastest lookup hands down. Just put an INT in the
data with 0. Then you can just use the keys.

Using a plain HashTable, that's a really bad idea - the 0 would get
boxed every time. Using something like "" or even making the key also
the value is more efficient.

 

[Joseph Geretz]

Thanks Jon,

I've been using "" for the value.

- Joe Geretz -

 

[Kevin Spencer]

Will this provide as efficient lookup as the HashTable?

What are you trying to look up?

--
HTH,

Kevin Spencer
Microsoft MVP

Printing Components, Email Components,
Networking Components, Controls, much more.
DSI PrintManager, Miradyne Component Libraries:
http://www.miradyne.net

Hi Rad,

An array?

Will this provide as efficient lookup as the HashTable?

Thanks,

- Joseph Geretz -

 

[Brian Gideon]

It might be a little early, but there will be the HashSet class in Orcas
which will introduce this class. Just something to be aware of in the
future.

I was not aware of that until now. I'm guessing it'll have union,
intersection, difference, etc. methods? That would be nice. Thanks
for the tip.