How can I use LINQ to find the Intersect between two properties of the same collection?

Posted by aponzani on Stack Overflow See other posts from Stack Overflow or by aponzani
Published on 2010-04-28T21:27:28Z Indexed on 2010/04/28 21:47 UTC
Read the original article Hit count: 234

Filed under:

LINQ

|

intersect

Given an IList<Foo> with a data set that looks like this:

ID   CHILD  PARENT TYPE  
1   102    101    UPSELL  
1   103    101    UPSELL  
2   102    101    BONUS  
2   104    103    BONUS  
3   102    101    BONUS  
4   102    101    PRODUCT  
4   104    102    PRODUCT

How can I use LINQ to find the intersection of Parent and Child values withing each ID? Desired output is

ID   CHILD  PARENT TYPE 
4   102    101    PRODUCT

© Stack Overflow or respective owner

Related posts about LINQ

LINQ to SQL, LINQ to XML and Accessing DataTable using LINQ

as seen on C# Corner - Search for 'C# Corner'
This article demonstrates how to use LINQ on DataTable, XML Data using LINQ to XML and SQL server data base using LINQ to SQL Classes. >>> More
Exception with Linq2SQL Query

as seen on Stack Overflow - Search for 'Stack Overflow'
I am running a query using Linq2SQL that comes down to following query: DateTime? expiration = GetExpirationDate(); IQueryable<Persons> persons = GetPersons(); IQueryable<Items> subquery = from i in db.Items where i.ExpirationDate >= expiration … >>> More
What is Linq?

as seen on ASP.net Weblogs - Search for 'ASP.net Weblogs'
The way data can be retrieved in .NET. LINQ provides a uniform way to retrieve data from any object that implements the IEnumerable<T> interface. With LINQ, arrays, collections, relational data, and XML are all potential data sources. Why LINQ?With LINQ, you can use the same syntax to retrieve… >>> More
Mixing Silverlight-Specific System.Xml.Linq dll with Non-Silverlight System.Xml.Linq dll

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a Logic layer that references Silverlight's System.Xml.Linq dll and a GUI that is in WPF (hence using the non-Silverlight System.Xml.Linq dll). When I attempt to pass an XElement from GUI project to a method in the Logic project, I am getting (basically) "XElement is not of type XElement" errors… >>> More
Subsonic 3 LINQ vs LINQ to SQL

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am using SQL Server 2005 in a project. I have to decide about datalayer. I would like to use LINQ in my project. I saw SubSonic 3 supporting LINQ and I also have option for LINQ to SQL, because i can have typed lists from LINQ to SQL. I am wondering what is different between LINQ to SQL and… >>> More

Related posts about intersect

SQLite INTERSECT gives a huge performance decrease

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a query that runs in less than 1 ms: SELECT product_to_value.category AS category, features.name AS featurename, featurevalues.name AS valuename FROM product_to_value, features, featurevalues WHERE product_to_value.category IN(:int, :bla, :bla1) … >>> More
mySQL experts - need help with 'intersect'

as seen on Stack Overflow - Search for 'Stack Overflow'
I know that mySQL 5.x does not support INTERSECT, but that seems to be what I need. Table A: Products (p_id) Table B: Prod_cats (cat_id) - category info (name, description, etc) Table C: prod_2cats (p_id, cat_id) - many to many prod_2cats holds the many (1 or more) categories that have been assigned… >>> More
Finding rows that intersect with a date period

as seen on SQL Blogcasts - Search for 'SQL Blogcasts'
This one is mainly a personal reminder but I hope it helps somebody else too. Let's say you have a table that covers something like currency exchange rates with columns for the start and end dates of the period each rate was applicable. Now you need to list the rates that applied during the year… >>> More
In SQL, if we rename INNER JOIN as INTERSECT JOIN, LEFT OUTER JOIN as LEFT UNION JOIN, and FULL OUTE

as seen on Stack Overflow - Search for 'Stack Overflow'
In SQL, the name Join gives an idea of "merging" or a sense of "union", making something bigger. But in fact, as in the other post http://stackoverflow.com/questions/2706051/in-sql-a-join-is-actually-an-intersection-and-it-is-also-a-linkage-or-a-sidew it turns out that a Join (Inner Join) is actually… >>> More
Intersect a collection of collections in LINQ

as seen on Stack Overflow - Search for 'Stack Overflow'
I've got a list of lists which I want to intersect: List<List<int>> input = new List<List<int>>(); input.Add(new List<int>() { 1, 2, 4, 5, 8 }); input.Add(new List<int>() { 3, 4, 5 }); input.Add(new List<int>() { 1, 4, 5, 6 }); Output should be { 4, 5… >>> More