I didn't know either Single() or SingleOrDefault(). In my application I have a list of items I need to sort by price and set a rank/position index for each item. How are engines numbered on Starship and Super Heavy? Weighted sum of two random variables ranked by first order stochastic dominance. Why did US v. Assange skip the court of appeal? Use MathJax to format equations. The OP since updated the question and having it makes no more sense at all since it's true 100% of the time. Is "I didn't think it was serious" usually a good defence against "duty to rescue"? How can I get the index of an item in a list in a single step? How can I control PNP and NPN transistors together from one pin? //d What does 'They're at four. "Signpost" puzzle from Tatham's collection. Why refined oil is cheaper than cold press oil? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Connect and share knowledge within a single location that is structured and easy to search. Weighted sum of two random variables ranked by first order stochastic dominance. What positional accuracy (ie, arc seconds) is necessary to view Saturn, Uranus, beyond? rev2023.5.1.43405. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. This article shows the three ways in which you can write a LINQ query in C#: Use query syntax. Use method syntax. Use a combination of query syntax and method syntax. The following examples demonstrate some simple LINQ queries by using each approach listed previously. Your code is O(n m), where n is the length of a and m is the length of b. Is a downhill scooter lighter than a downhill MTB with same performance? Canadian of Polish descent travel to Poland with Canadian passport. 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. 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? rev2023.5.1.43405. Since you want to change the properties of the elements in your enumeration, you should not be using linq or List.ForEach for that. However, those are all lamda expression style. I really don't understand why you say it's not meant for this. I just want something more concise that can be used more easily in a delegate without creating a multi-line monster. Why don't we use the 7805 for car phone chargers? Nevermind, actually you can get rid of the lambdas for a few cases Great answers! Making statements based on opinion; back them up with references or personal experience. Why did US v. Assange skip the court of appeal? User without create permission can create a custom object from Managed package using Custom Rest API. Adding EV Charger (100A) in secondary panel (100A) fed off main (200A). Has the cause of a rocket failure ever been mis-identified, such that another launch failed due to the same problem? When changes are cleared, I need to reset the times to MinValue. Thanks for contributing an answer to Stack Overflow! I'm querying to return every element of a List, so I can then set those values. Asking for help, clarification, or responding to other answers. 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. Why are players required to record the moves in World Championship Classical games? You can remove the .ToList call. If it really is a List you don't need LINQ, just use: If you are looking for the item itself, try: bool insertOrderNew = lOrders.Find(r => r == "1234") == null ? You can select multiple fields using linq Select as shown above in various examples this will return as an Anonymous Type. It's better to operate on List. 1. Thanks for contributing an answer to Stack Overflow! 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. Identify blue/translucent jelly-like animal on beach. Find centralized, trusted content and collaborate around the technologies you use most. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Where does the version of Hamapil that is different from the Gemara come from? Is a downhill scooter lighter than a downhill MTB with same performance? So simply iterate over that enumeration and set the new values: Note that I cut the trailing decimals by simple arithmetic instead of converting the values to strings and back. Could a subterranean river or aquifer generate enough continuous momentum to power a waterwheel for the purpose of producing electricity? Would My Planets Blue Sun Kill Earth-Life? The below is practically the same as the answer provided by Florian Schmidinger: Why don't we use the 7805 for car phone chargers? WebIf you really want to use linq, you can do something like this li= (from tl in li select new Myclass { name = tl.name, age = (tl.name == "di" ? At the moment I am doing it like this: You could do it using the let keyword. Use LINQ to get items in one List<>, that are not in another List<>, Simple deform modifier is deforming my object. In both cases , the update is not done with Linq :). To learn more, see our tips on writing great answers. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. One thing to note about using SingleOrDefault is that because it throws an exception if more than one match is in the list, it has to iterate through every item, where FirstOrDefault will stop searching once the first match is found. Also, you It can be done this way as well foreach (Company company in listofCompany.Where(d => d.Id = 1)).ToList()) Connect and share knowledge within a single location that is structured and easy to search. c# - ToList method in Linq - Stack Overflow To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The code looks like this: For the life of me, I can't seem to figure this one out. He also rips off an arm to use as a sword, Identify blue/translucent jelly-like animal on beach, Ubuntu won't accept my choice of password. Use method syntax. "Signpost" puzzle from Tatham's collection. Why refined oil is cheaper than cold press oil? This search will find the first or default value, which it will return. MathJax reference. It's not LINQ, and it's not really much different to your nested for loops, just slightly less verbose. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Boolean algebra of the lattice of subspaces of a vector space? Two points. Eric Lippert wrote a great blog post about the subject that is worth a read: "foreach" vs "ForEach". The property value is not changed. Folder's list view has different sized fonts in different folders. It only takes a minute to sign up. Find centralized, trusted content and collaborate around the technologies you use most. IEnumerable vs List - What to Use? is there such a thing as "right to be heard"? Besides checking for it's existance with if, first. Connect and share knowledge within a single location that is structured and easy to search. c# - how to query LIST using linq - Stack Overflow 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. However, one potential optimization could be realized in your foreach line as such: This would limit the set brought back to only those members that actually need their ToUpdate set rather than just setting them whether they need to or not. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 20 : 30)) I guess what I'm really saying here is I want a concise way to set all elements of a multi-dimensional array to a given value. It can be done this way as well foreach (Company company in listofCompany.Where(d => d.Id = 1)).ToList()) To learn more, see our tips on writing great answers. The best answers are voted up and rise to the top, Not the answer you're looking for? Making statements based on opinion; back them up with references or personal experience. 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. I just want to get a taste of LINQ searching from enumeration case. I like this. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. LINQ Approach (Likely Unnecessary) If you absolutely had to use LINQ, you could use a Select () call to map each of your existing elements to updated versions : // Asking for help, clarification, or responding to other answers. This assumes that there are only 3 types of name. 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 For the sake of the example, T in this case is an object similar to the following: Is there a way I can make this more efficient? How to call asynchronous method from synchronous method in C#? 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? I think your code is perfectly readable and won't improve much if you force it to have lots of lambdas and such. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Your first example is actually the correct method. 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. Certainly, the nested for loop works, and I can certainly place it in a function (which I have already done). Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. It's not them. 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? I have another List that contains the data, this just maps each element of the string array to a time when they last changed. "Signpost" puzzle from Tatham's collection. (from c in listOfCompany where c.id == 1 select c).First ().Name = "Whatever Name"; For Multiple updates. You can create a extension method: public static IEnumerable Do(this IEnumerable self, Action action) { 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. In general Linq is a query- not an update tool, but you can use a foreach: var currentRequests = var newList = correctionQoutas.Select(x => x.Value%1 != 0 ? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. When to use .First and when to use .FirstOrDefault with LINQ? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. correctionQoutas is a custom object that has four properties. How to set Name value as ID in List in c# using Linq? When do you use in the accusative case? Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, how to add more than one result to the list using a linq query, Concat all strings inside a List using LINQ, Using LINQ to remove elements from a List. It was designed to bring native data querying to .NET. 8 Answers. Find centralized, trusted content and collaborate around the technologies you use most. Ok, this should hopefully be of some help: I would also look into PLINQ as you have a lot of data to plow through. Asking for help, clarification, or responding to other answers. And the enumerable containing the objects isn't modified at all. See below for arguments against it. I need to store the rank because the price may change You can't modify a collection while you're iterating it. The below is practically the same as the answer provided by Florian Schmidinger: Thanks for contributing an answer to Stack Overflow! Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. I suspect that this can be written shorter using LINQ over objects syntax. Please read, Updating items of one List that match another List, How a top-ranked engineering school reimagined CS curriculum (Ep. Identify blue/translucent jelly-like animal on beach. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. How do I clone a list so that it doesn't change unexpectedly after assignment? Without digging into what your actual conversion function is doing. 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. Has the Melford Hall manuscript poem "Whoso terms love a fire" been attributed to any poetDonne, Roe, or other? c# - Select Multiple Fields from List in Linq - Stack Overflow Would My Planets Blue Sun Kill Earth-Life? 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. Be aware that it only updates the first company it found with company id 1. Which reverse polarity protection is better and why? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Should I re-do this cinched PEX connection? What is the symbol (which looks similar to an equals sign) called? 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. In my application I have a list of items I need to sort by price and set a rank/position index for each item. What is this brick with a round back and a stud on the side used for? Folder's list view has different sized fonts in different folders. Making statements based on opinion; back them up with references or personal experience. What are the advantages of running a power tool on 240 V vs 120 V? The check if you have decimal places is unneccessary too, since the output will be a double anyway. No symbols have been loaded for this document." Thanks for contributing an answer to Stack Overflow! Simple deform modifier is deforming my object. Also, Linq is only used here to loop over the collection, just like wudzik's answer. Two MacBook Pro with same model number (A1286) but different year. Did the drapes in old theatres actually say "ASBESTOS" on them? 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. ), Ubuntu won't accept my choice of password. Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, Sometimes when modifying properties in a foreach loop, the changes do not remain. Not the answer you're looking for? 10 : (tl.name == "marks" ? c# - Set list property value using LINQ ForEach - Stack Overflow I think you try to add a complete list instead of a single CheckItems instance. List Manipulation in C# using Linq - Stack Overflow Learn more about Stack Overflow the company, and our products. This new list is then discarded. 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. You could try something like this (not a pure LINQ approach): Here is one way, assuming a class structure as follows: You can join the second list on matching IDs: I think using Join then looping through the list would be more efficient. Besides, the LINQ equivalent probably wouldn't be any less verbose than my example above. Making statements based on opinion; back them up with references or personal experience. LINQ is not really intended to be used for updating collections. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Making statements based on opinion; back them up with references or personal experience. Why are players required to record the moves in World Championship Classical games? List Connect and share knowledge within a single location that is structured and easy to search. That's all it does. This should work Of course you can write your own ForEach extension for IEnumerable but I remember I had side-effect with it. Extract values from HttpContext.User.Claims, Ultrawingrid - Select row based on unique value, Concat all strings inside a List using LINQ, Using LINQ to remove elements from a 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, There are certainly ways to (ab)use LINQ to achieve the same results, but I'd consider them to be dirty hacks. A boy can regenerate, so demons eat him for years. What is the Efficiency and Performance of LINQ and Lambda Expression in .Net? this would be used for thing done to each date time as opposed to thing done with each date time That would be slightly different. If we need to find an element from the list, then we can use the Find and FindAll extensions method, but there is a slight difference between them. 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 What positional accuracy (ie, arc seconds) is necessary to view Saturn, Uranus, beyond? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. ex. (Your question does not sound like you want to copy the original objects). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Where can I find a clear diagram of the SPECK algorithm? Is there any known 80-bit collision attack? When do you use in the accusative case? What should I follow, if two altimeters show different altitudes? To learn more, see our tips on writing great answers. So, if you wanted to grab only a specific property from a collection you would use that. Not the answer you're looking for? Do I need to check if list is null first? Why did US v. Assange skip the court of appeal? Double StartTime, Double EndTime, Double Value and string Id. create enumerables over existing collections. Web14. Ubuntu won't accept my choice of password. c# - Add items to list from linq var - Stack Overflow To learn more, see our tips on writing great answers. foreach(var item in self) { Extracting arguments from a list of function calls. Is there any known 80-bit collision attack? What are the advantages of running a power tool on 240 V vs 120 V? It's exactly what I was looking for, How a top-ranked engineering school reimagined CS curriculum (Ep. For multiple. Where does the version of Hamapil that is different from the Gemara come from? What is Wario dropping at the end of Super Mario Land 2 and why? using Linq would be: listOfCompany.Where(c=> c.id == 1).FirstOrDefault().Name = "Whatever Name"; To use a linq statement to get a new List of CorrectionQuota you would do something like this: Transform the results into what you want first and then make the new List. Any suggestion? and MatchingColumnName1 and MatchingColumnName2 are properties of collections. As sircodesalot mentioned, you can't use linq to do something like that. WebThis is the best I have right now: var allCountries = repository.GetCountries (); var topitem = allCountries.Single (x => x.id == 592); var finalList = new List (); finalList.Add c# - Use LINQ to move item to top of list - Stack Overflow Should I re-do this cinched PEX connection? Generating points along line with specifying the origin of point generation in QGIS. (Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement). Generic Doubly-Linked-Lists C implementation, "Signpost" puzzle from Tatham's collection, Embedded hyperlinks in a thesis or research paper. is there such a thing as "right to be heard"? All values are updated in one line of code and you browse the List only ONE time. It's an easy way to filter out nulls. Great answer. He also rips off an arm to use as a sword. Is there a generic term for these trajectories? Why don't we use the 7805 for car phone chargers? 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. 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? Thanks for contributing an answer to Stack Overflow! Passing negative parameters to a wolframscript. How do I stop the Flickering on Mode 13h? If it is possible, how? Why did DOS-based Windows require HIMEM.SYS to boot? Unexpected uint64 behaviour 0xFFFF'FFFF'FFFF'FFFF - 1 = 0? Asking for help, clarification, or responding to other answers. To learn more, see our tips on writing great answers. The code will look something like this. true : false, Searches for the specified object and returns the index of the first occurrence within the list, Note that it returns -1 if the value doesn't occur in the list, This will help you in getting the first or default value in your LINQ List search. c# - assign value using linq - Stack Overflow
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