Questions tagged [linq]

Language INtegrated Query (LINQ) is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages.

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6
votes
2answers
669 views

C# - Linq - Techniques for avoiding repeating same pieces of code

I am writing a piece of code for C# Web Api, letting the clients to pass a column name and sort direction as parameter. Although there are, like, 30-ish properties, so the following code (despite it ...
1
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1answer
109 views

Eliminating repetitions of subsequent items in a list

I would like to convert a list A A = {1, 12, 3, 3, 3, 8, 5, 5 } into list B ...
0
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1answer
51 views

How to make this code follow Solid Principle C# [closed]

Currently I have this code: ...
1
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2answers
76 views

Finding duplicates in multiple lists for configuration validation

I have created helper class for configuration validation, the main purpose is to find any human "errors" in the configuration for the app. the case is that any type of "message" ...
-1
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1answer
85 views

Simplifying for loops that includes conditions with better linq queries

The code below selects all items that are locked. How can I optimise it? ShopItemData doesn't contain a field for locked/unlocked. ...
0
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2answers
95 views

Optimizing database access using LINQ [closed]

I have the following method that I am trying to optimize. Currently, the method works great, however, it takes a little over 3 hours to complete. I feel like, using some nifty LINQ joins, it should be ...
3
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1answer
199 views

A simple method to execute Entity Framework Core queries in parallel

As you might know, EF Core does not support executing multiple queries in parallel on the same context using something like Task.WhenAll. So you have to write this ...
4
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0answers
109 views

Repository pattern method implementation with entity framework and C#

I have two entities in my database: Employee and Shift. I want to implement a C# repository pattern method, that given two ...
6
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2answers
327 views

c# list object with view model child list

I am trying to build this view model that has a ChildViewModel and this was the only way I was able to get it working. Any advice on how to make this code; cleaner, more effective, just overall better!...
5
votes
3answers
129 views

Creating a CSV stream from an object

I have this code that gets a CSV string from a list of objects where the first row in the string is the object's properties and the rows underneath are the properties values. I then create a ...
2
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1answer
49 views

How do I make multithreading in sending large file from FTP to Azure large files faster

Currently, I have a code which downloads a file from FTP to local hard disk. It then uploads a file in chunks to Azure. Finally, it deletes the file from local and ftp. This code is very slow though. ...
5
votes
1answer
177 views

Compare List to Enum Where Contains Any

I have a List that I want to compare to an Enum. If a.Value is found in the Enum we return <...
2
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1answer
36 views

Iteration over an XDocument based on some existing elements and conditions

I wrote this piece of code which works as expected: ...
1
vote
1answer
53 views

Filter linq query

Any advice on how to make this code; cleaner, more effective, just overall better! Program has three options that can be passed int NewsId,Year and CategoryId. I collection all the data and then do ...
1
vote
2answers
108 views

Building a Word document containing two different tables

I am trying to generate a Word document with two different tables inside it. For this purpose I have two similar methods where I am passing word document reference and data object and table to the ...
1
vote
2answers
149 views

Protein Translation - Translate RNA sequences into proteins

RNA can be broken into three nucleotide sequences called codons, and then translated to a polypeptide like so: RNA: "AUGUUUUCU" => translates to Codons: <...
4
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3answers
264 views

Finding the string from the list of array objects

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4
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3answers
134 views

DistinctCount extension method

Here I go again. I have been finding a fairly common pattern in business logic code. And that pattern looks like this: ...
6
votes
5answers
356 views

Find greatest number in array that is a product of some two elements in the same array

Given an array a, find the greatest number in a that is a product of two elements in a. If there are no two elements in a that can be multiplied to produce another element contained in a, return -1. ...
6
votes
1answer
2k views

Async selector in LINQ

LINQ Select usually works like this: IEnumerable<Task<int>> res = new[] {1,2,3}.Select(async i => i); I would ...
4
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2answers
364 views

Big O notation for Reverse String

I have here some methods which reverse string characters. Example if given string is "HELLO", it will returns "OLLEH". Are my big o notation for these approaches correct? And which approach is the ...
6
votes
1answer
103 views

Picking a random neighbouring cell, but only picking previously-visited ones if there aren't any unvisited

I'm creating mazes, and have a Cell class (only relevant code shown)... ...
1
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0answers
322 views

SelectAsync With Max Degree Of Parallelism

I have been looking for the best approach to creating an extension method that would give me the ability to select in a linq query using async/await with a max degree of parallelism. I'm aware that ...
2
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0answers
67 views

Generic search service to filter entries in lists

I'm in the process of implementing a fully generic service to filter out entries (of any type), which are contained in a ICollection. As it is generic, without any ...
1
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0answers
47 views

Getting all descendants IWebElements (using XPath) is too slow in Selenium

Well, I'm working with Selenium to scrap a webpage that has obfuscated class names (example <div class="example-gHJkLM">...)... So I needed to create an ...
1
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0answers
86 views

get better performance [closed]

I have this code that works, but I'm sure that it can be done better, any suggestions? ...
2
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0answers
91 views

LINQ extensions for sequence comparing

The desired behavior would be: ...
3
votes
1answer
160 views

C# Linq search list within list

I am writing a domino draw game in C# and would like to know if there is a simpler/better way to know the player that has been dealt the highest double bone (where x equals y) and what bone it is: <...
4
votes
3answers
1k views

C# + Linq - grouping objects by frames of time found in the data

A bit of background. In the application I work on there are emails sent to notify users about articles they need to review. Each email+recipient pair is stored in database and may be assigned a ...
18
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6answers
6k views

Solving Fizz Buzz using LINQ in C#

The Fizz Buzz challenge is well-known and should not need any explanations, right? I recently got a bit bored and came up with a solution for Fizz Buzz using LINQ and even asynchronous code and a lot ...
12
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2answers
1k views

Given an array A[] and a number x, check for pair in A[] with sum as x

LINQ/FP style: Assert.IsTrue(new[] {1,2,3}.AnyPairSum(4)); Where: ...
4
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0answers
107 views

Implement Sudoku using LINQ

WiKi and GitHub. Sudoku rules are being checked with the following tests: ...
0
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0answers
62 views

GCD Groups with list

We have a list. divide the list element into two groups such that when the product of the numbers of two groups is taken and their GCD is calculated, it came out to be 1. Answer the number of ways in ...
7
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2answers
184 views

Iterate only once using LINQ

Funny thing, the following test works: ...
4
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1answer
93 views

Paginate IEnumerable<T> sequence

I used the following to split sequence into batches: ...
4
votes
2answers
133 views

Finding which items have at least one common value with other items

I have the following collection : ...
1
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1answer
98 views

ASP.NET MVC 5, EF 6 filter performance

I'm creating a filter with Linq in an ASP.NET MVC application. I was hoping I could get some tips on performance enhancements, aside from any possible performance enhancements. I have a few questions:...
8
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3answers
3k views

LINQ Extension methods MinBy and MaxBy

LINQ Extension I present a LINQ method ArgBy that returns the item of a sequence that corresponds to the predicate specified. Two additional methods ...
4
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2answers
123 views

Reverse Dictionary: Group from child array elements and get its minimum key

Objective I have following array and would like to group by each child and get its smallest Id:- ...
4
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2answers
191 views

DropDown tree with search

I fetch a bunch of categories for a DropDown tree, and have to implement search in this dropdown. If there is a match in one of the elements, it should also get all ...
5
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1answer
309 views

Make utility using LINQ

Make() takes projects with a list of tuples representing project references in the form of (Dependency, Dependent) and returns ...
6
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4answers
3k views

LINQ for generating all possible permutations

Permutate() is supposed to generate all possible permutations of the source sequence: ...
3
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1answer
116 views

LINQ for extracting N bottom items (async streams)

source.Bottom(n, x => x) should be the same as well known LINQ source.OrderBy(x => x).Take(n) but is more memory/run-time ...
9
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4answers
996 views

Filter search results by multiple filters in one operation

I want to filter search results by multiple filters at once. Is it possible to reduce the number of if statements? My code: ...
1
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0answers
333 views

E-Commerce Mock App in Console

I have completed this E-Commerce Mock App in Console C# which I used object to store the data to apply some C# OOP and LINQ techniques. Since it is just a mock version, features are reduced to the ...
17
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3answers
2k views

ExactlyOne extension method

I often find in codebases something on the order of if (sprockets.Count() > 0) which is easily replaced with LINQ's ...
5
votes
2answers
127 views

PLINQ code analysis in terms of efficiency of cryptographic hashes generation

I have the following code that I wrote in order to find the correct password by generating hashes out of all possible combinations and comparing each of them with the target. I'm trying to make ...
7
votes
5answers
655 views

Grouping into more groups in one iteration

I had a need to group the same dataset in several groups. So instead of repeatedly query the dataset, I made an extension that could do it once. The caveat is, that the result is materialized in ...
5
votes
3answers
493 views

SkipLast of an IEnumerable<T> - Linq Extension

As my answer to this question, I came up with this solution: ...
2
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1answer
132 views

Performance issue with empty lists

Here's my updated version of the problem I posted at Calculating time windows for entities, adding in suggested changes as well as a change I did so that the Reflection is 'cached' in a ...

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