Questions tagged [linq]
Language INtegrated Query (LINQ) is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages.
602 questions
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Sorting and filtering using dynamic parameters
I have this code which I am upgrading to .NET 8.
The intention is to sort and filter the resultset using the parameters. Right now it has a lot of if else and redundant code inside the blocks.
I would ...
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Optimizing LINQ Query on C# Web API
Can someone help me optimize this code especially the LINQ query. It takes 8-12 seconds just to return a response when I'm calling the endpoint. Its super slow, and my whole endpoint call is taking ...
2
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1
answer
230
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IEnumerable<T>.Tee implementation
I am trying to write A C# version of a method in the Java Stream API called Collectors.teeing() (It's like Aggregate but with multiple accumulator functions), just for educational purposes.
I want to ...
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Filter out nulls from sequence of nullables to produce sequence of non-nullables
While introducing nullable reference types to our enterprise application's codebase, I found that we are often using LINQ on sequences of nullable reference types where we filter out the nulls using <...
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Basic ATM Software from a Udemy Project
Recently starting to learn programming, I'm looking to move to making larger projects and am just picking up the basics now. I have a feeling this code sort of missed the point? Am looking for ...
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Project sequence to multiple sequences using LINQ (or extension methods)
I'm creating a method that expands a sequence.
This is a sample of how it works:
Input: {1, 2, 3}
Output: {1}, {1, 2}, {1,2,3}
So far, I've been able to solve the ...
- 233
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2k
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Transliterate between Cyrillic and Latin scripts
I want to get a code review on the following transliteration code. I wrote it because there were some libraries that I have tried and they were specifically failing with the name "Yuliya" ...
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2
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621
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Find the newest file that contains a specific string in every subdirectory of the path using the least resources
I have a server side logs folder that contains many hundreds of logs most of which are in subdirectories according to the machine the logs have come from. The task is to extract the full path of the ...
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1
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135
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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 ...
- 271
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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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397
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138
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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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134
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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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567
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135
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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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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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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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419
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1k
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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 ...
user40919
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1
answer
179
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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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92
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1
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2
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420
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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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240
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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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2
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191
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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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7k
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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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161
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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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2
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4k
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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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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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388
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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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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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2k
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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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96
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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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2
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208
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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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820
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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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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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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.
I ...
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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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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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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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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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473
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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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145
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Getting all descendants IWebElements (using XPath) is too slow in Selenium
Well, I'm working with Selenium to scrape a webpage that has obfuscated class names (example <div class="example-gHJkLM">...)...
So I needed to ...
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116
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4
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1
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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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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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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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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:
...
- 6,131
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Implement Sudoku using LINQ
WiKi and GitHub.
Sudoku rules are being checked with the following tests:
...
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