C# intersect performance
WebOct 1, 2024 · 4. The main reason for this big difference in performance is because you are using a culture-sensitive comparison for the case-insensitive hash set, whereas the case-sensitive hash set uses an ordinal one. Without passing the hash set any equality comparers, the hash set uses the default equality comparer of that type, which calls the … WebFrom performance point of view if two lists contain number of elements that differ significantly, you can try such approach (using conditional operator ?:): 1.First you need to declare a converter: Converter del = delegate (string s) { return Int32.Parse (s); }; 2.Then you use a conditional operator:
C# intersect performance
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WebJul 12, 2024 · Performance for these 3 variants is nearly identical. Conclusion It would seem the performance of LINQ is similar to more basic constructs in C#, except for that notable case where Count was ...
WebSep 7, 2024 · 2 Answers Sorted by: 3 I think it will be faster to use a join and group by like this: int numberOfFeatures = userToSearch.features.Count (); var userIds = from u in context.Users from uf in u.UserFeatures where userToSearch.features.Contains (uf.featuresId) group u by u.userId into g where g.Count () == numberOfFeatures select … WebYou can change fooKeys to HashSet (if it's not one already) to make Contains () method call O (1) instead of O (n): var keesSet = new HashSet (fooKeys); var matchedFoos = foos.Where (f => keesSet.Contains (f.Key)); But with collections that big it will still require a fair amount of time to perform the search. Share
WebI'm a little late to the party, but I think the cleanest and best way to fully emulate INTERSECT is: SELECT * FROM ( SELECT records.id FROM records, data WHERE data.id = records.firstname AND data.value = "john" ) x1 NATURAL JOIN ( SELECT records.id FROM records, data WHERE data.id = records.lastname AND data.value = … WebSep 7, 2012 · OK so for c# you should clearly do B.InsersectWith (A), if B << A. Intersect () is defined on IEnumerable and would be a lot less efficient based on the answers below (and MSDN). So the order does matter if you use the best tool, which is IntersectWith (). Update: OK so I forgot to mention this is a .NET question.
WebAug 3, 2010 · C# DemographicHashIntersectComparer demographicIntersectComparer = new DemographicHashIntersectComparer (); var updatedPatientInfos = newHashValues.Intersect (lastTransmittedHashes, demographicIntersectComparer); LINQ to SQL has an overridden Intersect method which allows us to pass our own custom …
WebFeb 10, 2010 · INTERSECT is meant to find the distinct values combining two queries. That's a very different goal than the INNER JOIN which is not finding distinct values, but values that simply match between... how big are tegusWebOct 10, 2010 · You can do it in C#: var results = q.AsEnumerable ().Select (x => new { x.k, PartialMatches = x.tags.Count (tag => input.Any ( word => word.Contains (tag))), ExactMatches = x.tags.Intersect (input).Count () }); The call to AsEnumerable () detaches this part of the query from the database. how many moves to solve rubik\u0027s cubeWebOct 27, 2024 · IntersectWith is a mutable operation where Intersect is immutable.This means that IntersectWith modifies duplicateWith whereas Intersect will generate a new … how big are the circles on a twister boardWebThe LINQ Intersect Method in C# is used to return the common elements from both collections. The elements that are present in both data sources are going to be returned by Intersect Method. There are two overloaded … how big are the dominos sandwichesWebOct 5, 2014 · It seems obvious that all the single-pass operations ( Select, Where, Count, Take/Skip, Any/All, etc.) will be O (n), since they only need to walk the sequence once; although even this is subject to laziness. how big are the dragons in game of thronesWebFeb 27, 2015 · Instead of using the IEnumerable<>.Intersect method you can do the same thing in a loop, but using the fact that you already have a hash set. Checking if a value exists in a hash set is very fast, so you can just loop through the items in the smallest set and look for matching values in the next set, and put them in a new set. how many moves does insect breathing haveWebFeb 1, 2024 · C# Intersection of two HashSets. A HashSet is an unordered collection of the unique elements. It is found in System.Collections.Generic namespace. It is used in a … how big are the chinese spy balloons