Get unique details from list

Question

0.00/5 (No votes)

See more:

I have following item objects in a List<Items>.

obj1 - ItemCode=001;
Name="aa";
Price=100;
PoNo=1;

obj2 - ItemCode=002;
Name="bb";
Price=200;
PoNo=2;

obj3 - ItemCode=001;
Name="aa";
Price=100;
PoNo=3;

obj4 - ItemCode=001;
Name="aa";
Price=250;
PoNo=4;

Now I want to take unique ItemCode and Price in PoNo. If same ItemCode and Price contains in different PoNo, Max PoNo should take.

Finaly output list should contains.
obj2,obj3,obj4

Posted 14-Nov-11 18:46pm

Sanyon_d

Add a Solution

Comments

Sergey Alexandrovich Kryukov 15-Nov-11 0:52am

Where is you LINQ here?
--SA

4 solutions

Solution 1

You are doing it wrong. As I can see, you need fast search by ItemCode. If so, don't use List.

Assuming the declaration is something like

C#

class Item {
   internal int ItemCode { get; set; }
   internal string Name { get; set; }
   //...
}

store your items in System.Collections.Generic.Dictionary<ItemCode, Item>, that is, the dictionary of Items indexed by ItemCode, see http://msdn.microsoft.com/en-us/library/xfhwa508.aspx[^].

Alternatively, use generic SortedDictionary or SortedList from the same name space. You want get any functional difference, only different trade-off between memory overhead and speed, pretty good in all cases, with complexity of O(1) (for understanding "Big O Notation", see http://en.wikipedia.org/wiki/Big_O_notation[^]).

—SA

Posted 14-Nov-11 19:01pm

Sergey Alexandrovich Kryukov

Comments

BillWoodruff 15-Nov-11 8:57am

In this case there are multiple items ... three of them ... with identical ItemCode values: so that excludes using those as Keys in a Dictionary.

But, I share what I believe is your underlying idea that some other form of data structure may be more useful here; imho, to help the OP design/optimize that structure we need to consider frequency of access by type of access.

Sergey Alexandrovich Kryukov 5-Apr-12 2:27am

Thank you, Bill.
Things are simple: there is a trade-off between redundancy and search speed. You correctly point out that the decision depends on frequency, but it also depends on the volume of data, requirements for speed of calculations and other factors.
--SA

Solution 3

Please describe this in more detail.

It appears to me you want a final result list that includes one of every object which either has a unique ItemCode ... or ... if there are multiple Items with the same ItemCode and which have all internal fields except PoNo match in Value ... then you wish to select one of those multiple items.

And, when two (or more) Items match in every way but the PoNo: you need make explicit ... if you are only choosing one of them ... what the basis for that choice is: first ? last ?

Based on the observation that Item1 and Item3 share all values except PoNo, and Item1's not in your final list result, I assume you want to take only the last unique instance with Itemcode 001 ... is that correct ?

Some other form of data structure than generic List may be a good fit here, but in order to discuss that, I think we need to know something about how the objects are accessed and used: what's the most frequent type of use here ?

If, as shown here, PoNo is a unique identifier for each object, that's a start.

Posted 15-Nov-11 3:00am

BillWoodruff

Solution 2

use LamdaExpression ..

http://gargmanoj.wordpress.com/2007/07/16/my-first-post-word-press/[^]

Check this out

Posted 15-Nov-11 2:27am

deepakdynamite

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Pandya Anil · Accepted Answer · 2011-11-15T03:08:00

Solution 4

C#

var result = (
            from f in foos
            from s in f.MyStrings
            select s).Distinct();

        // Which is absoulutely equivalent to:

        var theSameThing = foos.SelectMany(i => i.MyStrings).Distinct();

        // pick the one you think is more readable.

Posted 15-Nov-11 3:08am

Pandya Anil