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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"Select followed by First" versus "First followed by Select" when summing the data for a student

I am wondering which one I should choose between the following two options when I need to calculate the sum of Data of the student with ...
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0 votes
4 answers
1k views

Checking a value in a string array in C# [closed]

I want to see if there is a cleaner way to do this logic. I have a working sample: Same fiddle.net ...
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1 vote
2 answers
65 views

Is there a way to use lambda function to get the list?

I have a data set. ...
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1 vote
2 answers
93 views

Is there a way to simplify getting the character that appears the most in a collection with Linq?

I have a collection of strings, all of which are three characters in length: ...
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1 vote
2 answers
90 views

Efficiency of finding one database record using two ID's

I'm using C#, .NET Core and the entity framework and am currently working on optimizing various functions for better performance. One of the main functions is getting a calculation based on two ...
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1 vote
1 answer
64 views

Is there a nice way to add unique items from inner collections using LINQ method syntax

Code ...
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1 vote
1 answer
99 views

Reading data from a CSV and pushing it to a Salesforce application

I'm trying to write code that reads data from a CSV and pushes it to a Salesforce application using the API. My code processes the data in a for loop, but it takes a long time (3 hours) to run the ...
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0 votes
1 answer
1k views

Merging every two objects into single single object making group by a property C# LINQ [closed]

I have a object list like below. I want to join every two rows into single row based on column B. It is sure that only two rows would be there for every single column B value. Input Output However, ...
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-2 votes
1 answer
99 views

Can I refactor my code anymore? [closed]

I have written one method; however I feel I can refactor it even more but not sure what Can someone help me here? ...
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1 vote
0 answers
49 views

Optimizations on a function that fIlters a list of connections

Hello fellow programmers, I am currently implementing a function and wanted to know if there was anything I could change to simplify the code, make it more readable, or to optimize the running time ...
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0 votes
1 answer
148 views

Linq query to merge overlapping elements

I have this class representing a period of time: ...
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  • 101
6 votes
2 answers
885 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 ...
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1 vote
1 answer
126 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 ...
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1 answer
58 views

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

Currently I have this code: ...
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  • 121
1 vote
2 answers
102 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" ...
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-1 votes
1 answer
87 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. ...
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1 vote
2 answers
110 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 ...
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3 votes
1 answer
2k 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 ...
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4 votes
0 answers
130 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 ...
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6 votes
2 answers
2k 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!...
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  • 521
5 votes
3 answers
939 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 ...
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2 votes
1 answer
71 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. ...
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  • 121
5 votes
1 answer
3k 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 <...
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2 votes
1 answer
139 views

Iteration over an XDocument based on some existing elements and conditions

I wrote this piece of code which works as expected: ...
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1 vote
1 answer
57 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 ...
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  • 521
1 vote
2 answers
116 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 ...
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  • 189
1 vote
2 answers
358 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: <...
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  • 620
4 votes
3 answers
288 views

Finding the string from the list of array objects

...
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4 votes
3 answers
142 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: ...
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6 votes
5 answers
646 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. ...
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  • 620
8 votes
1 answer
7k 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 ...
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4 votes
2 answers
955 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 ...
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6 votes
1 answer
111 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)... ...
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1 vote
0 answers
777 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 ...
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2 votes
0 answers
96 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 ...
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  • 121
1 vote
0 answers
70 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 ...
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  • 227
1 vote
0 answers
86 views

get better performance [closed]

I have this code that works, but I'm sure that it can be done better, any suggestions? ...
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  • 111
2 votes
0 answers
95 views

LINQ extensions for sequence comparing

The desired behavior would be: ...
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3 votes
1 answer
278 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: <...
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  • 155
4 votes
3 answers
3k 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 ...
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18 votes
6 answers
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 ...
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12 votes
2 answers
2k 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: ...
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5 votes
0 answers
121 views

Implement Sudoku using LINQ

WiKi and GitHub. Sudoku rules are being checked with the following tests: ...
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0 votes
0 answers
67 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 ...
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7 votes
2 answers
277 views

Iterate only once using LINQ

Funny thing, the following test works: ...
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  • 6,123
4 votes
1 answer
219 views

Paginate IEnumerable<T> sequence

I used the following to split sequence into batches: ...
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  • 6,123
4 votes
2 answers
151 views

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

I have the following collection : ...
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  • 421
1 vote
1 answer
123 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:...
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  • 301
8 votes
3 answers
6k 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 ...
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4 votes
2 answers
396 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:- ...
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