Sorting Dictionary by Values

[Martin Pöpping]

Hello,

I´ve a simple question about existing data structures/ collections.

Is there a way to sort a dictionary (or any comparable collection/ data
structure) by values instead of by keys?

For example if you have a dictionary with words as keys and the
frequency of these words in a text as values.

What is the most performant way to sort these dictionary by the
frequency of the words (=values)?



Regards,

Martin

[John Timney \(MVP\)]

Re: Sorting Dictionary by Values

have you looked at the generic SortedDictionar y class

http://msdn2.microsoft.com/en-us/library/f7fta44c.aspx

--
--
Regards

John Timney (MVP)
VISIT MY WEBSITE:

http://www.johntimney.com

http://www.johntimney.com/blog

"Martin Pöpping" <martin_p@despa mmed.comwrote in message
news:ejcgev$ddg $1@newsreader2. netcologne.de.. .

Hello,
>
I´ve a simple question about existing data structures/ collections.
>
Is there a way to sort a dictionary (or any comparable collection/ data
structure) by values instead of by keys?
>
For example if you have a dictionary with words as keys and the frequency
of these words in a text as values.
>
What is the most performant way to sort these dictionary by the frequency
of the words (=values)?
>
>
>
Regards,
>
Martin

[Bill Block]

Re: Sorting Dictionary by Values

Two options:

1) Use a List<Timpelemen tation to store your data objects, then use
the Sort() method. For example:

List<MyClassm_l ist = new List<MyClass>() ;
m_list.Add(inst ance1);
m_list.Add(inst ance2);
m_list.Sort({Ge neric Comparison});

http://msdn2.microsoft.com/en-gb/library/w56d4y5z.aspx

2) Implement a custom sortable binding list implementation (if you need
binding as well). There is a good article on creating a
SortableBinding List in MSDN:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnforms/html/winforms02182005.asp

Bill

[Martin Pöpping]

Re: Sorting Dictionary by Values

John Timney (MVP) schrieb:

have you looked at the generic SortedDictionar y class
>
http://msdn2.microsoft.com/en-us/library/f7fta44c.aspx

Sure, but the SortedDictionar y sorts by Key and I want to sort
everything by value

[John Timney \(MVP\)]

Re: Sorting Dictionary by Values

oops - so it does.

Heres some code to sort the contents of the dictionary based on its values,
having key and vlaues both of type string. See if you can work with that.

Dictionary<stri ng, strings = new Dictionary<stri ng, string>();
s.Add("1", "a Item");
s.Add("2", "c Item");
s.Add("3", "b Item");

List<KeyValuePa ir<string, string>myList = new
List<KeyValuePa ir<string, string>>(s);
myList.Sort(
delegate(KeyVal uePair<string, stringfirstPair ,
KeyValuePair<st ring, stringnextPair)
{
return firstPair.Value .CompareTo(next Pair.Value);
}
);

foreach (KeyValuePair<s tring, stringmyKey in myList)
{
Response.Write( myKey.Key + " " + myKey.Value);
}


--
Regards

John Timney (MVP)
VISIT MY WEBSITE:

http://www.johntimney.com

http://www.johntimney.com/blog

"Martin Pöpping" <martin_p@despa mmed.comwrote in message
news:ejcrdn$1qr $1@newsreader2. netcologne.de.. .

John Timney (MVP) schrieb:

>have you looked at the generic SortedDictionar y class
>>
>http://msdn2.microsoft.com/en-us/library/f7fta44c.aspx

>
Sure, but the SortedDictionar y sorts by Key and I want to sort everything
by value

[Tony Gravagno]

Re: Sorting Dictionary by Values

This article by Eric Gunnerson at Microsoft was very helpful for
creating a sorted, enumerable hash table:

http://tinyurl.com/yj2x8a

I made a minor tweak to the IterSortHashVal ue code to return an Object
which can be used like a Hashtable for DropDownLists which exposes
both a Key and a Value.

I haven't compared any of these techniques and don't know if the OP
really needs to have a Dictionary or if that's just what he happens to
be looking at, at the moment.

HTH


"John Timney \(MVP\)" wrote:

>oops - so it does.
>
>Heres some code to sort the contents of the dictionary based on its values,
>having key and vlaues both of type string. See if you can work with that.
>
Dictionary<stri ng, strings = new Dictionary<stri ng, string>();
s.Add("1", "a Item");
s.Add("2", "c Item");
s.Add("3", "b Item");
>
List<KeyValuePa ir<string, string>myList = new
>List<KeyValueP air<string, string>>(s);
myList.Sort(
delegate(KeyVal uePair<string, stringfirstPair ,
>KeyValuePair<s tring, stringnextPair)
{
return firstPair.Value .CompareTo(next Pair.Value);
}
);
>
foreach (KeyValuePair<s tring, stringmyKey in myList)
{
Response.Write( myKey.Key + " " + myKey.Value);
}