linq remove duplicates from two lists

1. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, I have another class as property in the Items Class also, I agree.. ForEach should be used instead :), Thanks - was looking to avoid writing a comparer class so I'm glad this works :). duplicates Can somebody be charged for having another person physically assault someone for them? They both return a new sequence representing your original set Because a person can exist in various MarketingLists my EntityCollection can contain the same person multiple times. Connect and share knowledge within a single location that is structured and easy to search. For example suppose List1 = List and List2 = List. Look (Ive removed some of your code to make it simple): Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. [Solved]-Combine two list<> and remove the duplicates in it Release my children from my debts at the time of my death. Is it appropriate to try to contact the referee of a paper after it has been accepted and published? By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. (I tried to come up with a better example, but this is the best I could do right now.) linq It's not clear what to do if all records with some name don't have Dept, Distinct will use reference equality if the type does not implement IEquatable. you can use Linq by applying Distinct function with a custom comparer like the following code:. Find centralized, trusted content and collaborate around the technologies you use most. What's the DC of a Devourer's "trap essence" attack? Anyway, here are examples on how to 52. sppk.ToList().AddRange((data7k).ToList()); If you do not want to modify the original list then use Concat as suggested. My bechamel takes over an hour to thicken, what am I doing wrong. 1. I am new in C# and Linq I am facing one problem to remove duplicate records I need to Remove duplicate records those who don't have Dept. Hi there, I need to remove duplicates from a DataTable using LINQ. Sometimes the expense of splitting work out over multiple threads can take longer than just serially getting the job done. Thanks in advance. If list1 contains the same value in column 1 and column 3 as the list2, then I need to remove that item in list1. Show duplicate values while merging lists using Using robocopy on windows led to infinite subfolder duplication via a stray shortcut file. How can I avoid this? Tip: Union works on Lists and arrays. 3 solutions Most Recent Solution 1 Not clear if your question is asking to find duplicate in a list or in between two list. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Modified 4 months ago. Please see http://msdn.microsoft.com/en-us/library/bb348436.aspx for an example. Term meaning multiple different layers across many eras? To learn more, see our tips on writing great answers. How do I sort a list of objects based on an attribute of the objects? var distinctItems = items.GroupBy(x => x.Id).Select(y => y.First()); rev2023.7.24.43543. Thx for help. So you're considering a duplicate just as having the same name? Since you want to remove duplicates from your list you have to re-assign them to the list variable: oList = oList.Distinct ().ToList (). Flag all but one duplicates in a list. Remove Duplicates I only measured the given function. Is saying "dot com" a valid clue for Codenames? WebI'm having trouble coming up with the most efficient algorithm to remove duplicates from List>, for Well I know I can sort each element in that instance and those two will end up the same, so for the purposes here I'll say no. Anthology TV series, episodes include people forced to dance, waking up from a virtual reality and an acidic rain. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. How to remove string by format in VB .NET?!! What is the most efficient way to remove duplicates in an IList in C# without Linq. condition 1 So you want to remove all items which are duplicates? Here is one way to do it: List duplicates = lst.GroupBy (x => x) .Where (g => g.Count () > 1) .Select (g => g.Key) .ToList (); The GroupBy groups the elements that are the same together, and the Where filters out those that only appear once, leaving you with only the duplicates. Union function in LINQ remove duplicate entries consider: {Name=abe, Surname=long} and {Name=abel, Surname=ong} would both get the GroupBy key "abelong" if a delimiter isn't used. Objects in Collection1 have a field called Name, objects in Collection2 have a field called Field. (Bathroom Shower Ceiling), Anthology TV series, episodes include people forced to dance, waking up from a virtual reality and an acidic rain, Find needed capacitance of charged capacitor with constant power load. I'm looking for a clean way to make sure the lists match up (again, order doesn't matter) and it supports duplicates. Those will get you the ones that have a department. WebThe process of removing duplicates from a list using LINQ involves calling one of several LINQ methods, such as Distinct (), GroupBy (), or creating a HashSet from the list, which Remove duplicates based on a condition What is the smallest audience for a communication that has been deemed capable of defamation? How can I retrieve Id of inserted entity using Entity framework? minimalistic ext4 filesystem without journal and other advanced features. Remove duplicates and sum values in minimalistic ext4 filesystem without journal and other advanced features. Linq 0. get distinct rows between two lists. Hopefully this could help. Anthology TV series, episodes include people forced to dance, waking up from a virtual reality and an acidic rain. Remove duplicates using linq. Find centralized, trusted content and collaborate around the technologies you use most. I forgot about the .Contains() method. Therefore I want to get the duplicates but only the duplicate primary keys, therefore .Union() does not work. How can kaiju exist in nature and not significantly alter civilization? Attempting to merge two Lists I use the List for aggregate the string read from database, but I have duplicates in this string. Find needed capacitance of charged capacitor with constant power load. @Olli1511 allrigth then. 2. How does hardware RAID handle firmware updates for the underlying drives? Compare Two Lists Thanks for contributing an answer to Stack Overflow! customer.Category); Sorry I never read the text on StackOverFlow just the code. retainAll(list2) will remove all entries, that does not exist in list2. Share. Removing duplicates that appear more than once, Remove and get duplicates in a list in C#. To compare two List and extract their differences, I use Linq's Except. Is there a way to speak with vermin (spiders specifically)? WebYou have three option here for removing duplicate item in your List: Use a a custom equality comparer and then use Distinct(new DistinctItemComparer()) as @Christian Hayter mentioned. removeAll(list2) will remove all entries, that does exist in list2. Fiddle that demonstrate that. linq - Combining 2 lists and and remove duplicates .Output in a WebComapring two List to extract the common items and put it in List. Asking for help, clarification, or responding to other answers. Is that the same as List resultList = listOne.Union(listTwo).ToList(); I still get duplicates though ,may be is something wrong with my customers examples, I know this post is old, but for anyone facing the same problem: Your customers might be two different objects with the same name. Found hints here: LINQ to Entities - where..in clause with multiple columns. 6. 1 - Get rid of your pipe separated string (create an dto class corresponding to the data it's representing). How to remove an element from a list by index. Use a delegate for the equality comparer for LINQ's Distinct(), C# Distinct on IEnumerable with custom IEqualityComparer, Left join on two Lists and maintain one property from the right with Linq, Combine two list<> and remove the duplicates in it. How difficult was it to spoof the sender of a telegram in 1890-1920's in USA? Another alternative is to GroupBy the fields that are important and take any item from the group (since the GroupBy acts as .Equals in this case). Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. Is it appropriate to try to contact the referee of a paper after it has been accepted and published? WebSource: stackoverflow.com. Remove duplicates with lambda leaving last item (from dupes) alive. I have the following list. Do not rely on the comments section to add critical information. The ToList creates a new list with the distinct strings. Why do capacitors have less energy density than batteries? How did this hand from the 2008 WSOP eliminate Scott Montgomery? public DataTable RemoveDuplicateRows(DataTable dTable, string colName) { Hashtable hTable = new Hashtable(); ArrayList duplicateList = new ArrayList(); //Add list of all the unique item value to hashtable, which stores combination of key, value pair. I have a class Items with properties (Id, Name, Code, Price). remove repeated items in a list unity; jquery remove duplicates from array; c# list remove duplicate items; find duplicates in lists with LINQ and get count; remove duplicates sql server select; c# list remove item based on property duplicate; grep remove duplicates; kotlin remove duplicates from list; query to remove duplicate Why is this Etruscan letter sometimes transliterated as "ch"? Remove Duplicates From a List in C# - Code Maze Why does ksh93 not support %T format specifier of its built-in printf in AIX? Was the release of "Barbie" intentionally coordinated to be on the same day as "Oppenheimer"? Using Linq to remove duplicate by column values based on a second column. Find centralized, trusted content and collaborate around the technologies you use most. Generalise a logarithmic integral related to Zeta function, Is this mold/mildew? Ask Question Asked 9 years ago. Select distinct by two properties in a list. marseilles84. Trying to remove duplicates from a list where a duplicate is when either the first, the second or both properties are equal (appear more than once in the list). My custom class has various items in which one is DCN number and list has only DCN number. My bechamel takes over an hour to thicken, what am I doing wrong. I am trying to merge two lists using list.Union in LinqPad but I can't get it to work and wanted to check my understanding is correct.. What happens if sealant residues are not cleaned systematically on tubeless tires used for commuters? Is it appropriate to try to contact the referee of a paper after it has been accepted and published? You can remove duplicates using the Distinct operator. List lstEmployeeSalary = new EmployeeSalaryFactory ().GetRelatedObjects (inValue, ddlPayDate, payRollType, payrollSearch) .Select (m => WebWe then create a new List from the HashSet and return it. I need to remove those duplicate record those who dont have dept. I always seem to have a problem when I need to compare 2 list and produce a 3rd list which include all unique items.I need to perform this quite often. customer.Name, output example:-. English abbreviation : they're or they're not. For example consider the following example: Which is incorrect because it considers {Id = 3, Name = "Item3", Code = "IT00004", Price = 250} as duplicate. C# SQL/Linq/Entity Framework calculating column totals for multiple columns from large data source. 592), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned. 1. using System.Collections.Generic; 2. using System.Linq; ToDictionary would also be an option, instead of ToLookup, if each key is unique, but that's a step backwards into the heavyweights. Thanks for any suggestions. Physical interpretation of the inner product between two quantum states. What's the most efficient way to remove one of the duplicate lists of "A students"? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, @ScottChamberlain To be fair - I do not believe the, @ScottChamberlain In that case you could sort within the, Using Linq to remove duplicate by column values based on a second column, Improving time to first byte: Q&A with Dana Lawson of Netlify, What its like to be on the Python Steering Council (Ep. two I want to remove c3. Airline refuses to issue proper receipt. Is saying "dot com" a valid clue for Codenames? I could suggest that you go one step further and flatten the results purely in LINQ and then do a single "foreach" loop to delete. The ways to find difference of two lists has been discussed earlier, but sometimes, we require to remove only the specific occurrences of the elements as much they occur in other list. +1 This solution even allows for a tie-breaker: eliminate duplicates with criteria! English abbreviation : they're or they're not. 1 Answer. Remove duplicate items from KeyValuePair List by Value, LINQ's Distinct() on a particular property, Update all objects in a collection using LINQ. Webvar duplicates = test.GroupBy(x => new {x.checkThis, x.checkThat}) .Where(x => x.Skip(1).Any()); I know I can put the first statement into an if else clause. Ask Question Asked 3 years, 7 months ago. it make more sense than the text ;) Is it possible to split transaction fees across multiple payers? 3. as i said my list is to big and i think it's not recommended to use another list. How feasible is a manned flight to Apophis in 2029 using Artemis or Starship? To learn more, see our tips on writing great answers. ! Remove duplicate comparing two large lists efficiently in C#? IList> output = new List>(); var lists = output; for (int i = 0; i < lists.Count; ++i) { //since we want to compare sequecnes, we shall ensure the same order of the items var item = (same problem as in my first solution). minimalistic ext4 filesystem without journal and other advanced features. Compare Two Lists Duplicates vs Unique - Excel from duplicates and remove duplicates in @Cleptus: Then there's two questions. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, Remove duplicate records using LINQ [duplicate], Improving time to first byte: Q&A with Dana Lawson of Netlify, What its like to be on the Python Steering Council (Ep. You can also do var set = new HashSet (); var uniques = items.Where (x => set.Add (x.Id));. linq I have a datatable with two columns "DT" and "ASOF", both dates. I need some help using a lambda expression to remove duplicate entries in my Entity Framework context. Webvar totalList = Featured .Concat (Filtered.Except (Featured)) .ToList () This will return all the Featured items, followed by all the Filtered items that were not Featured. Is there any other way using LINQ to compare these two lists via the TypeID? Term meaning multiple different layers across many eras? 1 - Create Custom generic comparer for List:. to remove duplicate strings of list string List 1: Apple, Banana, Apple. Compare id's of objects in two lists and get the list of objects that includes objects with ids occurring in This would probably be fairly efficient. Release my children from my debts at the time of my death. Print out to the console. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. But, as Victor Juri suggested below: use FirstorDefault. ID? Also one more case is here since List1 contains various items , other items values might be different but the DCN must be same. What are some compounds that do fluorescence but not phosphorescence, phosphorescence but not fluorescence, and do both? So you will want to include the appropriate using-directive. Here we are specifically doing group with "AId because in your duplicate rows the dates are different, Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Find centralized, trusted content and collaborate around the technologies you use most. How to remove (via linq) duplicates from a List of objects. What you need to do is to add an comparator for the Column class and then try: var distinctColumns = columns .Distinct (new ColumnComparer ()); Share. rev2023.7.24.43543. Remove duplicates Thanks Richard, please look at my other question There I have explained myself better with the full code. Find centralized, trusted content and collaborate around the technologies you use most. C#. So in this case i need 1400 as my output List as list1. Here is a class: class IPInfo { public String TRADE_DATE; public String CUSTOMER_NAME; public List ORIGINAL_IP; public List LOGON_IP = new List (); } The List fields has records with my codes are like below : EDIT : var merged = list1.Union (list2, new PersonComparer ()); By that we've come full 592), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned. The second allows you to supply your own equality comparer. remove duplicates rev2023.7.24.43543. I have the following list. Example 2: List 1: Apple, Banana. Query a list for only duplicates. Specifically, I need to filter out all duplicates for a single column, maintaining the initial Datatable strucutre. 7. How to remove duplicates from a list What would kill you first if you fell into a sarlacc's mouth? Do I have a misconception about probability? Note that there are two custom classes involved. Is it appropriate to try to contact the referee of a paper after it has been accepted and published? That's is another approach. Unfortunately my question is ignored and tagged as a duplicate without being observed carefully. You can group the items by the sum of p2, order the groups by p1 in descending order, then take the first one from each group in order to remove the duplicates.. You can also make the method static, since it doesn't need instance data:. This will make a huge difference in speed if the list is large.. Now if your list is a List<>, you can use the RemoveAll() method:. remove duplicates Comparing two lists with duplicates to remove duplicates from List without LINQ Removing almost-duplicates from nested list Not the answer you're looking for? The goal is to have the duplicates added to a third list, call it list3. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. How can I randomly select an item from a list? mean. Here I have a list of Column objects. The idea is to group the items by the two properties and then pick the "best" item from each group. You should use, @CameronMacFarland The problem is that I have another List as property for my, Should I overwrite the GetHashCode()` and. Why is this Etruscan letter sometimes transliterated as "ch"? Why can't sunlight reach the very deep parts of an ocean. duplicate thanks for answer / but some duplicate email addrress in that list have different parts -> what can i do about them (mean : goodzila@yahoo.com|32432|test23 and goodzila@yahoo.com|asdsa|324234), How to remove duplicates from List without LINQ? How to remove time portion of date in C# in DateTime object only? Error: Cannot implicitly convert type 'System.Collections.Generic.IEnumerable>' to 'System.Collections.Generic.List>'. Release my children from my debts at the time of my death. Retrieving non-duplicates from 2 Collections using LINQ linq Remove duplicates from EntityCollection Apr 29, 2021 at 8:40 C# LINQ find duplicates in List and remove one. As a rule I use a unique delimiter to combine fields so that two items that should be different don't unexpectedly combine to the same key. How does hardware RAID handle firmware updates for the underlying drives? Do I have a misconception about probability? I can think of a for loop that will be able to do this by creating an array of the duplicates, finding the newest ASOF, and then removing all others from the DB table with that value. List with duplicate information using Linq Since the ID is unique you could use this approach (Dept seems to be a string): This keeps only the first employee with empty Dept. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, Thanks for your reply. Thanks for contributing an answer to Stack Overflow! Remove duplicates from List(Of 592), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned. Connect and share knowledge within a single location that is structured and easy to search. 33. 592), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned. There are two overloads - one uses the default equality comparer for your type (which for a custom type will call the Equals () method on the type). When I added another 'txt4' to the end of your list only one duplicate instance was removed and two were left. Does the US have a duty to negotiate the release of detained US citizens in the DPRK? .GroupBy(a => And what if two employees have same name, but different age? What information can you get with only a private IP address? I want to insert random elements into a existing database. 1. We don't want to remove/retain on the original lists, because this will modify it, so we copy them, in the constructor. 0. source list : the important part of each item is email address and the other parts(separated with pipes are not important) but i want to keep them in final list. Nice work. How to remove the duplicates in the list using linq? Now I just need to add more than one property (composite primary key) but I can do this on my own! The lookup should then be pretty close to O(1) (assuming a fair hashcode distributation) instead of O(n) - bringing the overall complexity of the algorithm from O(n * k) down to O(n + k). It will take the first instance found for each duplicate (sorry for the obj - obj2 notation, it is just sample code): list.SelectMany (obj => new MyObj [] {list.Where (obj2 => obj2.Name == obj.Name).First ()}).Distinct (); To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Is this mold/mildew? Hope it helps. If necessary, you can use the Distinct() overload that takes an IEqualityComparer to create custom equality comparisons. WebThe process of removing duplicates from a list using LINQ involves calling one of several LINQ methods, such as Distinct (), GroupBy (), or creating a HashSet from the list, which will automatically remove duplicates. Is there a way to speak with vermin (spiders specifically)? How do I split a list into equally-sized chunks? How to combine two lists without duplication? Remove duplicates from a List in C# I have a data reader to read the string from database. WebCombining 2 lists and and remove duplicates .Output in a third list .My attempts do not work. Can a Rogue Inquisitive use their passive Insight with Insightful Fighting? Term meaning multiple different layers across many eras? Is it a concern? Comparing two lists and removing each item that contains Do the subject and object have to agree in number? Csharp Programming Server Side Programming. Remove duplicates The Union method will work with 2 collections of the same type of elements. WebI'm having trouble preserving the duplicates when comparing two List objects. Find centralized, trusted content and collaborate around the technologies you use most. 2 - which rule do you want to apply to select two object with the same id ? List Array. 592), Stack Overflow at WeAreDevelopers World Congress in Berlin, Temporary policy: Generative AI (e.g., ChatGPT) is banned. Any suggestion would be highly Could ChatGPT etcetera undermine community by making statements less significant for us? WebBackground: I have two Collections of different types of objects with different name properties (both strings). You can create an extension method similar to ToDictionary() with the difference being that it allows duplicates. Remove duplicate objects from a list using LINQ in c# In post is linq to MoreLinq project @nawfal, I was suggesting FirstOrDefault() in lieu of First(). Is it a concern? How feasible is a manned flight to Apophis in 2029 using Artemis or Starship? I have tried using two methods but none didn't turns for better result Data table contains more than 10 columns but unique column's is "Barcode", "ItemID", "PackTypeID" Method-1: Was the release of "Barbie" intentionally coordinated to be on the same day as "Oppenheimer"? Remove duplicate object after compare 2 list, C# Removing Duplicates from a List Containing a List. linq How can I animate a list of vectors, which have entries either 1 or 0? If you override .Equals (and .GetHashCode) then .Distinct would use it to eliminate duplicates. Thanks for contributing an answer to Stack Overflow! Linq Join Duplicates records c# Remove duplicate objects from a list using LINQ in c# [duplicate], Improving time to first byte: Q&A with Dana Lawson of Netlify, What its like to be on the Python Steering Council (Ep.

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