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" ? 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. Use LINQ to get items in one List<>, that are not in another List<>. Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey. How is this any different? Asking for help, clarification, or responding to other answers. I'm using VS 2008. I have my doubts that my box is 18,000 times faster than yours, so something else must be at work here. For Starship, using B9 and later, how will separation work if the Hydrualic Power Units are no longer needed for the TVC System? You can create a extension method: public static IEnumerable Do(this IEnumerable self, Action action) { 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. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Here is one way to rewrite your method to use LINQ: public static int GetItemIndex(string search) { List _list = new List() { "one", "two", 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? What should I follow, if two altimeters show different altitudes? rev2023.5.1.43405. To learn more, see our tips on writing great answers. The list may be a class with several properties and some are used for search. I want to do: Just change all values for a property in all elements of my collection. Parabolic, suborbital and ballistic trajectories all follow elliptic paths. Can I use the spell Immovable Object to create a castle which floats above the clouds? What were the most popular text editors for MS-DOS in the 1980s? Why did US v. Assange skip the court of appeal? Very useful. You can't modify a collection while you're iterating it. At the moment I am doing it like this: You could do it using the let keyword. 1. Asking for help, clarification, or responding to other answers. Do you want the item in the list or the actual item itself (would assume the item itself). This should work Of course you can write your own ForEach extension for IEnumerable but I remember I had side-effect with it. Not the answer you're looking for? foreach(var item in self) { Can anyone help me with a working expression? Asking for help, clarification, or responding to other answers. What is the best way to give a C# auto-property an initial value? Connect and share knowledge within a single location that is structured and easy to search. It doesn't work. 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? Not the answer you're looking for? I have a bit of code that i'd like to turn into a linq expression (preferably with lambdas) to make it easier to use as a delegate. Two MacBook Pro with same model number (A1286) but different year. 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. 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; }) Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. warning? rev2023.5.1.43405. Why don't we use the 7805 for car phone chargers? Why are players required to record the moves in World Championship Classical games? In general Linq is a query- not an update tool, but you can use a foreach: var currentRequests = Should I re-do this cinched PEX connection? Use .ToList () in order to convert query in list that you can work with. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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. What is this brick with a round back and a stud on the side used for? If you want to modify all returned objects, you still have to use a loop to iterate over the objects. Would My Planets Blue Sun Kill Earth-Life? 8 Answers. Thanks for contributing an answer to Stack Overflow! Web3. Asking for help, clarification, or responding to other answers. Be aware that it only updates the first company it found with company id 1. I didn't know either Single() or SingleOrDefault(). In both cases , the update is not done with Linq :). (Your question does not sound like you want to copy the original objects). Why does Acts not mention the deaths of Peter and Paul? I disagree, it is in fact a query, but a query with side effects. The ToList is making a list, populating it, and the immediately discarding it. Connect and share knowledge within a single location that is structured and easy to search. Thanks for contributing an answer to Stack Overflow! Adding EV Charger (100A) in secondary panel (100A) fed off main (200A). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. See below for arguments against it. There are many such queries used in Linq, such as projecting transofrmation, etc.. There's no -1 index (not found) in my example. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Reme. Thanks. Folder's list view has different sized fonts in different folders. Certainly, the nested for loop works, and I can certainly place it in a function (which I have already done). How can I get the index of an item in a list in a single step? For multiple. 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. is there such a thing as "right to be heard"? //d Making statements based on opinion; back them up with references or personal experience. I used to use a Dictionary which is some sort of an indexed list which will give me exactly what I want when I want it. He also rips off an arm to use as a sword. Use method syntax. Find centralized, trusted content and collaborate around the technologies you use most. Why did DOS-based Windows require HIMEM.SYS to boot? The list IS updated as expected. I have a list where i whant to change the value of a double property in that list if that property has decimals. How can I control PNP and NPN transistors together from one pin? There are certainly ways to (ab)use LINQ to achieve the same results, but I'd consider them to be dirty hacks. It's exactly what I was looking for, 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. When do you use in the accusative case? If we had a video livestream of a clock being sent to Mars, what would we see? UPDATE This can be simplified to be listOf and MatchingColumnName1 and MatchingColumnName2 are properties of collections. I think I'm not undertanding LINQ well. In my application I have a list of items I need to sort by price and set a rank/position index for each item. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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. Why? Is a downhill scooter lighter than a downhill MTB with same performance? 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. { Which was the first Sci-Fi story to predict obnoxious "robo calls"? You should iterate your list, and modify your values like: foreach (var student in myList) { if (student.Name == "Tom") { student.Marks = 35; } } Or foreach (var student Connect and share knowledge within a single location that is structured and easy to search. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. "Signpost" puzzle from Tatham's collection. However, those are all lamda expression style. Why don't we use the 7805 for car phone chargers? An interesting question, but Linq is about querying and what you're doing here doesn't look much like a query to me. What positional accuracy (ie, arc seconds) is necessary to view Saturn, Uranus, beyond? 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? Has the Melford Hall manuscript poem "Whoso terms love a fire" been attributed to any poetDonne, Roe, or other? 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Find centralized, trusted content and collaborate around the technologies you use most. When to use .First and when to use .FirstOrDefault with LINQ? //d it will be discarded but, how will you replace older list values? The property value is not changed. Concat all strings inside a List using LINQ, Using LINQ to remove elements from a List. I need to store the rank because the price may change afterward. 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, Moving List View items from one list to another, Best way of updating a list of unique items, Find items in a table that match a set of conditions in another table, Multiple similar manager classes for handling scroll lists, Recursive search on Node Tree with Linq and Queue, Collecting data into objects and POSTing to 3rd Party API, Python scripts that generate valid ngrams for use in pseudoword generation. 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. The check if you have decimal places is unneccessary too, since the output will be a double anyway. 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? I use a simple list here. Find centralized, trusted content and collaborate around the technologies you use most. Is there any known 80-bit collision attack? Which reverse polarity protection is better and why? How a top-ranked engineering school reimagined CS curriculum (Ep. This search will find the first or default value, which it will return. 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. How do I get the number of elements in a list (length of a list) in Python? How do I make a flat list out of a list of lists? You can select multiple fields using linq Select as shown above in various examples this will return as an Anonymous Type. How can I control PNP and NPN transistors together from one pin? What is the symbol (which looks similar to an equals sign) called? Nevermind, actually you can get rid of the lambdas for a few cases Great answers! Could a subterranean river or aquifer generate enough continuous momentum to power a waterwheel for the purpose of producing electricity? Embedded hyperlinks in a thesis or research paper. Was Aristarchus the first to propose heliocentrism? is there such a thing as "right to be heard"? I mean, if PopulateChanges() is returning you a List<> of DateTime arrays, and you are going through all of them and setting them to DateTime.MinValue, what exactly is the code unit that you want to put in the delegate? 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. 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? Where does the version of Hamapil that is different from the Gemara come from? // Next, when I try to add vnlist to vendlist, I get an error as I cannot add this to the list I get and error saying I have some invalid arguments. Why is it shorter than a normal address? Note that this will throw if the item doesn't exist. The following example depicts the behavior of the Enumerable.Distinctmethod on a 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. It's an easy way to filter out nulls. List1 and List2 are two collections. Weighted sum of two random variables ranked by first order stochastic dominance. Let me try to look it up. You need change increment to postfix (rankPosition++) or initial value of rankPosition to 0. It's about querying, i.e. It's also a violation of the expectations involved with LINQ - LINQ is about querying, which suggests there shouldn't be side effects when using LINQ, and the entire purpose here is to create side effects. Thanks for contributing an answer to Stack Overflow! Short story about swapping bodies as a job; the person who hires the main character misuses his body. (Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement). Passing negative parameters to a wolframscript. You're trading one assignment for one condition, that shouldn't change much. Or use (list ?? Use LINQ to get items in one List<>, that are not in another List<>, Simple deform modifier is deforming my object. Connect and share knowledge within a single location that is structured and easy to search. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Where does the version of Hamapil that is different from the Gemara come from? Without digging into what your actual conversion function is doing. A boy can regenerate, so demons eat him for years. 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. How to call asynchronous method from synchronous method in C#? Generating points along line with specifying the origin of point generation in QGIS. Which reverse polarity protection is better and why? I suspect that this can be written shorter using LINQ over objects syntax. It's not them. Canadian of Polish descent travel to Poland with Canadian passport. Not the answer you're looking for? 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. Using LINQ to change values in collection, How a top-ranked engineering school reimagined CS curriculum (Ep. Can I use my Coinbase address to receive bitcoin? 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. Asking for help, clarification, or responding to other answers. What positional accuracy (ie, arc seconds) is necessary to view Saturn, Uranus, beyond? Can you perhaps include some description of your answer instead of just posting a blob of code? What positional accuracy (ie, arc seconds) is necessary to view Saturn, Uranus, beyond? FYI, I know that DateTime defaults to MinValue, in reality this is clearing the arrays to default after they've already been set. Which ability is most related to insanity: Wisdom, Charisma, Constitution, or Intelligence? Note that you can add a ForEach extension method which performs an action on each object, but I would still recommend avoiding that. Web14. AddRange takes an enumerable, and it will enumerate it all on its own. Why are players required to record the moves in World Championship Classical games? 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? from c in listOfCompany where c.id == 1 select c => Making statements based on opinion; back them up with references or personal experience. If it is possible, how? I just want to get a taste of LINQ searching from enumeration case. Remember that linq is a querying language, which means all you can do is query it. What does 'They're at four. You can create a extension method: public static IEnumerable Do(this IEnumerable self, Action action) { Identify blue/translucent jelly-like animal on beach. rev2023.5.1.43405. Why refined oil is cheaper than cold press oil? But,in my case, I must repeat the foreach in many collections, and I didn't want to repeat the loop. Why refined oil is cheaper than cold press oil? Use MathJax to format equations. But then, at this point, you're better off (with less typing) doing it the "clear" way: This is shorter, very clear in its intent, and very clean. How are engines numbered on Starship and Super Heavy? > var boys = new List {"Harry", "Ron", "Neville"}; > boys.IndexOf ("Neville") 2 > boys [2] == "Neville" True This will help you in getting the first or default value in your LINQ List search This search will find the first or default value, which it will return. How to force Unity Editor/TestRunner to run at full speed when in background? Is a downhill scooter lighter than a downhill MTB with same performance? Your code is O(n m), where n is the length of a and m is the length of b. IEnumerable vs List - What to Use? I need to store the rank because the price may change This appears to be a response to another answer rather than an answer to the question. This will give syntax error, How to set a value in one list when comparing it with other list using LINQ, How a top-ranked engineering school reimagined CS curriculum (Ep. 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. Asking for help, clarification, or responding to other answers. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. If I understand you correctly you have to enumerate your nested array for several different reasons and would like to encapsulate that functionality to be reused.. When do you use in the accusative case? If you want to create a new List with each element set to a value, you can do this: var changes = Enumerable.Range (0, width) .Select (x => I found SingleOrDefault to be my answer of choice - same as Single but returns 'null' if it can't find it. LINQ stands for Language Integrated Query. Short story about swapping bodies as a job; the person who hires the main character misuses his body. How do they work? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 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 you really want to use linq, you can do something like this. Here I have a simple example to find an item in a list of strings. When to use .First and when to use .FirstOrDefault with LINQ? If x.Value has decimals, I want to change that value to take just the first decimal woithout rounding it. Why waste the time on it. and do I need to check if _list is null in the form of from .. in _list? 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 code will look something like this. Whenever I wish to access my margins values, for instance, I address my dictionary: So, depending on what you're doing, a dictionary can be useful. Find centralized, trusted content and collaborate around the technologies you use most. Is there a generic term for these trajectories? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Asking for help, clarification, or responding to other answers. 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. Not the answer you're looking for? To learn more, see our tips on writing great answers. If you need to add any IEnumerable collection of elements to the list you need to use AddRange. Does a password policy with a restriction of repeated characters increase security? 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. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. How do I remedy "The breakpoint will not currently be hit. Can I use my Coinbase address to receive bitcoin? Learn more about Stack Overflow the company, and our products. 1. There's not a single query in LINQ that modifies the queried collection (hence "query"). When changes are cleared, I need to reset the times to MinValue. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. It will, except for one small detail the numbering will start from 2. Great answer. There are several different ways to accomplish but here is one using linq and one with out this would allow you to reuse this and do different things to each item. To learn more, see our tips on writing great answers. 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.
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