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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4
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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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2
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1
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2
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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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2
answers
90
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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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1
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1
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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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1
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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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0
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49
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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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2
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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
1
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1
answer
126
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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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1
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58
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1
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2
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102
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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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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
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2
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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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1
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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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130
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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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2k
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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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3
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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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1
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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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1
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3k
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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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2
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1
answer
139
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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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1
answer
57
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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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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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2
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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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3
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288
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4
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142
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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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6
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5
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646
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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.
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1
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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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4
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2
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955
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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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1
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111
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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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0
answers
777
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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 ...
- 171
2
votes
0
answers
96
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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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0
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70
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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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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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0
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3
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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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3
answers
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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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6
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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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2
answers
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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:
...
- 6,123
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0
answers
121
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Implement Sudoku using LINQ
WiKi and GitHub.
Sudoku rules are being checked with the following tests:
...
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67
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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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151
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Finding which items have at least one common value with other items
I have the following collection :
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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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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
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2
answers
396
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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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