Try this, var products = from listProducts in repository.All() where listProducts.Code == “48654” group listProducts by listProducts.family into grp select grp; For more information visit LINQ Group By 0 solved How to use GroupBy in LINQ? [duplicate]
You could try something like this: recordsEpP.Where(row=> !string.IsNullOrEmpty(row.Column20) && !string.IsNullOrEmpty(row.Column14) && string.IsNullOrEmpty(row.Column8) ).Select(row => new ReportDto{ Status = “P”, ContractNumber = row.ContractNumber, Count = 1 }).ToList(); 0 solved How to re-write this linq from query syntax to method syntax? [closed]
Treating this as a kind of code-golf, the following gives an idea as to how you can approach the problem from a functional mindset, where you try and ‘flow’ the results of one function through another (which is presumably what your manager is after). Some changes are possible: Replacing the if with a filter predicate … Read more
You could use GroupBy on an anonymous type with both properties to make them distinct: var coursesList = from c in not_subsribe group c by new { Id = c.Cours.ID, Name = c.Cours.Name } into g order by g.Key.Name select new SelectListItem { Text = g.Key.Name, Value = g.Key.Id }; That works because an anonymous … Read more
You are using FirstOrDefault so you are returning only the first. PromotionList dataPromotion = authenticateCustomerResponseRootObject.Response.AuthenticateCustomerResponse.EligiblePromotions.PromotionList.Where(p => p.LineOfBusiness.ToUpper().Equals(“Data”)).FirstOrDefault(); If you want all of them just remove that call at the end and replace with a ToList, ToArray or similar that meets your needs: var data = authenticateCustomerResponseRootObject.Response.AuthenticateCustomerResponse.EligiblePromotions.PromotionList.Where(p => p.LineOfBusiness.ToUpper().Equals(“Data”)).ToList(); Also as mentioned in the comments your … Read more
You’re comparing apples and oranges. Each of the approaches you list has benefits and drawbacks, so it’s impossible to answer which is the “preferred way.” Likewise, many of these examples will return immediately because they use deferred execution, so they’ll technically run faster, but won’t actually make your program run any faster. But if you’re … Read more
Yes you can’t! The IEnumerable generates new Lists every time it is evaluated; it says so right there in your code: .Select(x => new List<int>{x}); When you call Dump(), it is evaluated. When you call First(), it’s evaluated again. Then Dump again. All new Lists! If you evaluate the IEnumerable before putting it in the … Read more
This cannot be done because once the class definition is set, that’s it. The best you can do to retrieve an array of only the Name and Address properties contained in an object is to use LINQ to perform an operation on each element, in which case you can then retrieve an array of anonymous … Read more
You could try following code, it uses private field to stroe all permutations generated by methods finding permutations: private static List<string> _permutations = new List<string>(); public static Main(string[] args) { string testString = “abc”; TestMethod(testString); // You need to handle case when you have last permuation in a list string nextPermutation = _permutations[_permutations.IndexOf(testString) + 1]; … Read more
you’re comparing string and char type replace where r1[4] == “I” / where r1[4] == “O” with where r1[4] == ‘I’ / where r1[4] == ‘O’ 3 solved LINQ Operator ‘==’ cannot be applied to operands of type ‘char’ and ‘string’
var summary = FullList .GroupBy(p => p.product_id) .Select(g => new { product_id = g.product_id, product_name = g.First().product_name, quantity = g.Sum(p => p.quantity) }) .ToList(); As an exercise think about Concat for getting all the depot names. 2 solved C# + get list from list [closed]
there can ba multiple values that match the condition – Dictionary<int, decimal> dict = new Dictionary<int,decimal>(); dict.Add(1, 392.3m); dict.Add(2, 612m); dict.Add(3, 981m); dict.Add(4, 344.23m); List<int> Result = dict.Where(x => x.Value < 400).Select(x => x.Key).ToList(); 0 solved How can you select and filter dictionary keys based on their values using Linq?
public class ClassBEqualityComparer : IEqualityComparer<ClassB> { public bool Equals(ClassB x, ClassB y) { if((x.var2.Equals(y.var2)) && (x.var3.SequenceEqual(y.var3)) && (x.var4.SequenceEqual(y.var4))) { return true; } else { return false; } } public int GetHashCode(ClassB x) { } } public class ClassAEqualityComparer : IEqualityComparer<ClassA> { public bool Equals(ClassA x, ClassA y) { ClassBEqualityComparer ClassBEqC = new ClassBEqualityComparer(); if((x.Type == … Read more
Neither. Using a loop has less overhead than LINQ, so that is a good start. Use the < operator in the loop condition, that is the standard way of writing such a loop, so it’s more likely that the compiler will recognise it and optimise it properly. Using Math.Pow to square a number is not … Read more
Not much to it – it’s just how the code was written. Take a look at the docs and you’ll see – Exceptions ArgumentNullException – source is null. InvalidOperationException – source contains no elements. Makes sense though. You can’t get an average from zero items. 2 solved Average of empty list throws InvalidOperationException: Sequence contains … Read more