how to set value in list using linq c#
Google "LINQ side effects" for more information. is there such a thing as "right to be heard"? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, This question is difficult/dangerous to answer without misleading people into thinking that LINQ is an appropriate solution to your problem. To learn more, see our tips on writing great answers. List If you make your expression return a value, and add something that will fully evaluate the query, such as ToList(), to the end, then it will "work", ie: That being said, ToList() has some disadvantages - mainly, it's doing a lot of extra work (to create a List) that's not needed, which adds a large cost. Find centralized, trusted content and collaborate around the technologies you use most. In my application I have a list of items I need to sort by price and set a rank/position index for each item. The only difference between them is that the .First method will throw an exception if there is no such object in the collection when the second one returns the The code looks like this: For the life of me, I can't seem to figure this one out. What does LINQ return when the results are empty, Use LINQ to get items in one List<>, that are not in another List<>. (from c in listOfCompany where c.id == 1 select c).First ().Name = "Whatever Name"; For Multiple updates. And the enumerable containing the objects isn't modified at all. Has the cause of a rocket failure ever been mis-identified, such that another launch failed due to the same problem? The check if you have decimal places is unneccessary too, since the output will be a double anyway. How can I control PNP and NPN transistors together from one pin? How to set Name value as ID in List in c# using Linq? How can I control PNP and NPN transistors together from one pin? It's not LINQ, and it's not really much different to your nested for loops, just slightly less verbose. rev2023.5.1.43405. Is there any known 80-bit collision attack? Eric Lippert wrote a great blog post about the subject that is worth a read: "foreach" vs "ForEach". Which method performs better: .Any() vs .Count() > 0? But,in my case, I must repeat the foreach in many collections, and I didn't want to repeat the loop. I would externalize that part into a function to make it more manageable. Why are players required to record the moves in World Championship Classical games? Why did US v. Assange skip the court of appeal? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The i.age = 10 part is not different from the item.age = 10 part. I think you try to add a complete list instead of a single CheckItems instance. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, There is no ForEach for IEnumerable. c# - Use LINQ to move item to top of list - Stack Overflow Has the Melford Hall manuscript poem "Whoso terms love a fire" been attributed to any poetDonne, Roe, or other? Why did DOS-based Windows require HIMEM.SYS to boot? Is there any known 80-bit collision attack? I pass a List a using ref, along with another List b. I need to cycle thru List b, which contains around 200,000 items, and for each item in b, it it matches criteria in a, which contains 100,000 or more items, and update it. I think using Join then looping through the list would be more efficient. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Do I need to check if list is null first? It's better to operate on List. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. 1. Why don't we use the 7805 for car phone chargers? I think I'm not undertanding LINQ well. I want to do: Just change all values for a property in all elements of my collection. Asking for help, clarification, or responding to other answers. It should not be hard to analyze the complexity of this. How do I split a list into equally-sized chunks? Without digging into what your actual conversion function is doing. Connect and share knowledge within a single location that is structured and easy to search. Not the answer you're looking for? Folder's list view has different sized fonts in different folders. When new changes occure, then those elements get a new DateTime. A boy can regenerate, so demons eat him for years. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. What were the most popular text editors for MS-DOS in the 1980s? There's no -1 index (not found) in my example. create enumerables over existing collections. Since you want to change the properties of the elements in your enumeration, you should not be using linq or List.ForEach for that. Should I re-do this cinched PEX connection? AddRange takes an enumerable, and it will enumerate it all on its own. At this point, the Select option is far uglier, more typing, etc. Update all objects in a collection using LINQ, LINQ's Distinct() on a particular property, Deserializing JSON to .NET object using Newtonsoft (or LINQ to JSON maybe? Was Aristarchus the first to propose heliocentrism? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Weighted sum of two random variables ranked by first order stochastic dominance. Has the cause of a rocket failure ever been mis-identified, such that another launch failed due to the same problem? LINQ stands for Language Integrated Query. If the null hypothesis is never really true, is there a point to using a statistical test without a priori power analysis? If you want to create a new List with each element set to a value, you can do this: If you really want to do it using ForEach/LINQ, it's possible to abuse Select (but I don't recommend it): Can you describe some use cases of how you propose to use the said delegate? When do you use in the accusative case? Folder's list view has different sized fonts in different folders. When to use .First and when to use .FirstOrDefault with LINQ? Is a downhill scooter lighter than a downhill MTB with same performance? Embedded hyperlinks in a thesis or research paper. Use MathJax to format equations. If you had a more generic collection IEnumerable, you can use Select in Linq to build a projection where property will be set as desired (original collection will be left untouched!): listOfRequestAssigned .Where (x => x.RequestedNumber == CurrentRequest) .Select (x => { x.RequestCompleted = true; return x; }) Thanks for contributing an answer to Stack Overflow! Besides checking for it's existance with if, first. "Signpost" puzzle from Tatham's collection. Or use (list ?? According to this link: Update all objects in a collection using LINQ, you can do this: repo.getAll().Select(c => {c.B = value; return c;}).ToList(); However, Extracting arguments from a list of function calls. Making statements based on opinion; back them up with references or personal experience. x.Value = Convert.ToDouble(string.Format("{0:0.0}", x)) : x.Value = x.Value); This gives you an Do you want the item in the list or the actual item itself (would assume the item itself). Is a downhill scooter lighter than a downhill MTB with same performance? Code Review Stack Exchange is a question and answer site for peer programmer code reviews. Asking for help, clarification, or responding to other answers. Here is one way to rewrite your method to use LINQ: You can use FirstOfDefault with the Where LINQ extension to get a MessageAction class from the IEnumerable. Your code is O(n m), where n is the length of a and m is the length of b. how to check for a value in a list of decimal C#, C# Select From Json List Using Where Clause, String search function XML file with ASP.NET MVC. If the null hypothesis is never really true, is there a point to using a statistical test without a priori power analysis? To learn more, see our tips on writing great answers. Thanks. Thanks for contributing an answer to Code Review Stack Exchange! Why? Assigning a value to a parameter of an lambda does not change the queried collection Linq expression to set all values of an array to a given value, How a top-ranked engineering school reimagined CS curriculum (Ep. Connect and share knowledge within a single location that is structured and easy to search. Great answer. Since you haven't given any indication to what you want, here is a link to 101 LINQ samples that use all the different LINQ methods: 101 LINQ Samples. As sircodesalot mentioned, you can't use linq to do something like that. I've tried using ForEach and various forms of select, etc.. nothing seems to work right. What you could do, if you don't want to do it the first way and if your collection is a list already (but not an IEnumerable) you can use the ForEach extension method in linq to do what you're asking. //using linq list = Students.Where (s => s.Name == "ABC").ToList (); //traditional way foreach (var student in Students) { if (student.Name == "ABC") list.Add 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. User without create permission can create a custom object from Managed package using Custom Rest API. You need change increment to postfix (rankPosition++) or initial value of rankPosition to 0. Generic Doubly-Linked-Lists C implementation, "Signpost" puzzle from Tatham's collection, Embedded hyperlinks in a thesis or research paper. Simple deform modifier is deforming my object. I need to store the rank because the price may change Find centralized, trusted content and collaborate around the technologies you use most. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Please read, Updating items of one List that match another List, How a top-ranked engineering school reimagined CS curriculum (Ep. Adding EV Charger (100A) in secondary panel (100A) fed off main (200A). MathJax reference. I just want to get a taste of LINQ searching from enumeration case. In general Linq is a query- not an update tool, but you can use a foreach: var currentRequests = Making statements based on opinion; back them up with references or personal experience. "Signpost" puzzle from Tatham's collection, Simple deform modifier is deforming my object. Close enough for me, I think. Why are players required to record the moves in World Championship Classical games? It can be done this way as well foreach (Company company in listofCompany.Where(d => d.Id = 1)).ToList()) Following the logic of the first example, we could use, msdn.microsoft.com/en-us/library/bb342451(v=vs.110).aspx, How a top-ranked engineering school reimagined CS curriculum (Ep. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Note that this will throw if the item doesn't exist. To learn more, see our tips on writing great answers. c# - Find an item in a list by LINQ - Stack Overflow When do you use in the accusative case? I need to store the rank because the price may change afterward. While you can use a ForEach extension method, if you want to use just the framework you can do collection.Select (c => {c.PropertyToSet = value; return How can I control PNP and NPN transistors together from one pin? I want to compare these lists using LINQ and if IDs from both lists are equal, I want to set WorkingID in the first list, A list. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Nevermind, actually you can get rid of the lambdas for a few cases Great answers! The following example depicts the behavior of the Enumerable.Distinctmethod on a By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Making statements based on opinion; back them up with references or personal experience. Would My Planets Blue Sun Kill Earth-Life? Which reverse polarity protection is better and why? What are the advantages of running a power tool on 240 V vs 120 V? Use LINQ to get items in one List<>, that are not in another List<>. LINQ is about querying, not for updating collections. Concat all strings inside a List using LINQ, Using LINQ to remove elements from a List. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. How do I make a flat list out of a list of lists? rev2023.5.1.43405. Can anyone help me with a working expression? Not knowing the full extent of the data types behind the MatchA, MatchB and ToUpdate properties, it'll be difficult to give an answer which completely solves your performance issues. When to use .First and when to use .FirstOrDefault with LINQ? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Write LINQ queries in C# | Microsoft Learn To learn more, see our tips on writing great answers. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Also, Linq is only used here to loop over the collection, just like wudzik's answer. It only takes a minute to sign up. What does 'They're at four. c# - conditional Updating a list using LINQ - Stack Overflow It can be done this way as well foreach (Company company in listofCompany.Where(d => d.Id = 1)).ToList()) Set list property value using LINQ ForEach. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, No offense, but this seems like using Linq for the sole purpose of using linq, not because it's actually solving a problem (as a matter of fact, it's created a problem), I may be wrong, but I thought there is no, How a top-ranked engineering school reimagined CS curriculum (Ep. Would My Planets Blue Sun Kill Earth-Life? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Linq expression to set all values of an array to a given value rev2023.5.1.43405. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. See below for arguments against it. The list IS updated as expected. Has the cause of a rocket failure ever been mis-identified, such that another launch failed due to the same problem? Not the answer you're looking for? Are there any canonical examples of the Prime Directive being broken that aren't shown on screen? Using LINQ to change values in collection, How a top-ranked engineering school reimagined CS curriculum (Ep. What is Wario dropping at the end of Super Mario Land 2 and why? Not the answer you're looking for? Hm, using your example and stuffing various random data into the objects into the two lists of the sizes you specify, it executes in less than 1/100 second on my machine. The OP since updated the question and having it makes no more sense at all since it's true 100% of the time. Which reverse polarity protection is better and why? Making statements based on opinion; back them up with references or personal experience. Why does Acts not mention the deaths of Peter and Paul? Query a collection of objects (LINQ in C#) | Microsoft Learn How is this any different? Asking for help, clarification, or responding to other answers. from c in listOfCompany where c.id == 1 select c => I have a list where i whant to change the value of a double property in that list if that property has decimals. I'm trying this but can't get it right: This solves the problem by resorting to nullable ints: If you want to count the number of items that match: And don't forget to check the list for null in any of these cases. You could make it O ( n + m) (assuming only a small number of items from a match each item in b) by using a hash table. If you need to transform the elements, then you need to use the Select() LinQ function: This gives you an IEnumerable, to freeze the contents and actually do the evaluation, you can use the ToList() function after the Select() function. Ok, this should hopefully be of some help: I would also look into PLINQ as you have a lot of data to plow through. rev2023.5.1.43405. rev2023.5.1.43405. Making statements based on opinion; back them up with references or personal experience. Does a password policy with a restriction of repeated characters increase security? Passing negative parameters to a wolframscript. Thanks for contributing an answer to Stack Overflow! What positional accuracy (ie, arc seconds) is necessary to view Saturn, Uranus, beyond? LINQ is not really intended to be used for updating collections. List1 and List2 are two collections. Asking for help, clarification, or responding to other answers. There's not a single query in LINQ that modifies the queried collection (hence "query"). You have also a way to set a default value. If you need to add any IEnumerable collection of elements to the list you need to use AddRange. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. If we had a video livestream of a clock being sent to Mars, what would we see? Connect and share knowledge within a single location that is structured and easy to search. Use method syntax. Thanks for contributing an answer to Stack Overflow! Can these methods be used with other collections too like, @yellavon these are extension methods on any type that implements. Be aware that it only updates the first company it found with company id 1. All I am doing is creating a working example, as my FYI says.. i'm really caling just the for loop part of it (the rest is just setup) in an area that's different from this. Single will return a single result, but will throw an exception if it finds none or more than one (which may or may not be what you want): Note that SingleOrDefault() will behave the same, except it will return null for reference types, or the default value for value types, instead of throwing an exception. You're trading one assignment for one condition, that shouldn't change much. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Which language's style guidelines should be used when writing code that is supposed to be called from another language? First, there's no real need to use. Adding EV Charger (100A) in secondary panel (100A) fed off main (200A), Folder's list view has different sized fonts in different folders. Can I use my Coinbase address to receive bitcoin? What positional accuracy (ie, arc seconds) is necessary to view Saturn, Uranus, beyond? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Sorry, guys. This new list is then discarded. What's the cheapest way to buy out a sibling's share of our parents house if I have no cash and want to pay less than the appraised value? c# - assign value using linq - Stack Overflow
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how to set value in list using linq c#
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how to set value in list using linq c#
We got our robust technical support team. Members of this team are well experienced and knowledgeable. In addition we conduct virtual meetings with our BCs to update the development in the banking and the new initiatives taken by Bank and convey desires and expectation of Banks from BCs. In these meetings Officials from the Regional Offices of Bank of Baroda also take part. These are very effective during recent lock down period due to COVID 19.
how to set value in list using linq c#
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