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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Selecting employees in certain departments using LINQ
I am trying to select the DepartmentName from Employee Table based on where condition. Is any way to simplify the code?
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Linq group by with multiple where, sum clauses in select causes a timeout
I have linq query that extracts a summary of my sales quantities item group wise. This query causes an sql ...
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Entity Join slow query
I've never participated in a codereview before and I was pointed that I should in another thread for a slow query.
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Test helper method to assert if text could be found
Lately I've been getting a lot of critique in my code reviews at work, where typical comments have been that my variable names are unclear/confusing, flow in method could be simplified, unnecessary ...
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Copy an Entity With Navigation Property in C#
I have a table named Asset and each Asset has schedules. I create a method like this for copying an entity:
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Concise code to perform action on every element, when need index
When I read this answer, which has code:
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Get first DateTime by given weekdays and a starttime
At work there is an input-system where customers are able to specify weekdays and a starting time for an event. The weekdays are integers in the range from 1 (Monday) to 7 (Sunday).
After the customer ...
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Filtering data on basis of attribute values
I am writing code to filter data on basis of attribute values. It is possible that the user can select multiple values.
How can this be better?
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Splitting a list of numbers into multiple lists
I need split the list I get from the select into multiple list so I can use Parallel.For() to generate the next query in different threads.
I create the main list
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Multiple enumerations of IEnumerable
I have a snippet of code here that uses C# and Linq. The ganttData variable I have has 12 warnings stating:
possible multiple enumerations of IENumerable
Should ...
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Join via navigation properties with collection
There are some related collection objects in my table and I'm trying to get list with joining this tables. But this code is seems bad:
Entities that shortened:
User:
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LinQ wrapper to get distinct items from a IEnumerable based on a function of item
I often need to perform LinQ queries to get distinct items from a IEnumerable based on one of its properties. I would like to know if this is a good way to wrap this operation:
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Locating people by roleId
Basically, I'm trying to find all active people with a roleId of 3 (analyst id). But I want to exclude ids that were created as test analysts, i.e. "130", "252", ...
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Linq-like functions in JavaScript
Today was my first day working with JavaScript and I tried to implement some Linq-like (C#) functions as extension methods.
I'm pretty new to JavaScript and wanted to ask you for checking my ...
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Linq query combining three tables [closed]
I have a linq query that combines three tables:
Users,
Products, and
User_Has_Products
I ...
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IQueryable left outer join linq extension
I wanted to create an extension method to enable left outer joins in linq/lambda IQueryables, and I have come up with the following, but I am still not sure it's completely correct.
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Updating database based on selected check boxes
I posted the original question here, but I think it would be nice to have someone else's eye on this code for improving it.
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Constructing file paths for each row of a datatable in C#
I need to iterate through a DataTable and columns in each rows and do some data manipulation.
Below given is an extract from my code, I use c#.net. I expect maximum rows in datatable will be less ...
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Get XML elements with a particular attribute value
I have the following code to find xml elements that have a particular attribute value:
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LINQ to SQL query filter, with the name match ignoring multiple punctuation characters
I have the following LINQ to SQL query which works fine but looks ugly:
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Climbing the stairs
A quick description on the problem I solved on codewars.com but remember I just want a small part of my solution refactored (just the for-loop):
Description
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Sort and merge list based on another list
Here I'm merging a list to end of another list after sorting it according to another list.This should sort processdetails list according to the order in routeplans list if any item not present in ...
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Check if the user exists
Scenario:
Check if the user exists
If yes: update the details
Else: insert the user details
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Using LINQ to group social networking links for each user
I have a model named User. Each user can have some social links. Now I want to get all users with their social link as a single row in the result. Here are my ...
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Country code lookup for each line in a CSV file
I'm trying to write a program that has a for loop, inside of which I have lambda expression to get a certain value. The loop has about 20,000 iterations. Including ...
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Transform a List of objects to a string of unique values for use in an SQL query
I have a List of Results. My goal is to extract the Result property ...
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HackerRank woman codesprint: minimum cost
Lauren has a chart of projected prices for a house over the next n
years, where the price of the house in the i-th year is <...
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IQueryable Extensions working on expression for collection property
Followup to Repository searching code duplication
My goal currently is to make the current implementation of my repository's IQueryable filtering less duplicative. First, I looked into passing ...
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Migrating data using entity framework, linq and recursion
I have a piece of code to migrate data from an old app to a new app. The data represents the user's websites.
In the old app the user only had one section for websites, on which you could add any ...
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Retrieving website categories from a three-level hierarchy
I've been trying to fix this performance bottleneck in my web app for a while now.
Here is what the data looks like on my web page:
Here is how I get this data in the controller:
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Unfold a 2D array spiral in C#
The purpose of this function is to turn a 2D array of sorts into a single-dimensional array by reading it in a spiral fashion.
In the array:
1 2 3
4 5 6
7 8 9
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Pangrams implementation using Linq
This is a continuation of my LINQ stories from Pangrams-Hackerrank. Similarly, this challenge has been asked before in python Pangrams python Implementation but I have tried to accomplish this ...
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Diagonal difference using Linq
Recently, I have been trying my hands on LINQ. So I've implemented the diagonal difference using Linq in Hackerrank. I know a similar question has been asked in python Diagonal Difference
Here is an ...
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Implementing SOLID Principles - LINQ TO SQL
I have been using Layered Architecture in my web application. Can anyone please advise if my data layer classes (both Linq and booking class) can be improved?
I have just started learning about solid ...
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Chunking a list into separate lists of 5, and then iterating through each
I'm writing a service that receives a list of Latitude/Longitude objects, prepares them for transaction, and then calls a web service to write them to the organization's Mainframe. According to the ...
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Filtering data for jQuery DataTables
Using DataTables (Table plug-in for jQuery) with server-side processing, I had to create filtering for my data with good performance. However, in my opinion it's kinda ugly, especially the part of (<...
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Too Many Staff Meetings
I recently got in really deep on a question to find the overlapping meetings and I rewrote a bit of the code and added some things to the code, and I would just like a general review of my code and ...
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Creating monthly files from an annual file
I am interested in learning a more succinct (or better performing) way of writing the following working code. I just figured it out but it is pretty messy. This program takes a file full of daily ...
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Delete records from multiple tables when deleting a subproject [closed]
In my program I am deleting subprojects using LINQ. It's incredibly slow. There is a lot of cascade on delete's here so I am deleting from multiple tables. Any help and tips would be appreciated.
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Factoring WHERE clauses in IQueryable
I recovered some spaghetti code and I have to refactor it. I do not want a method with over 200 lines, for me it is not object oriented programming. I am trying to ponder on the question and would ...
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Reading in a file and ranking result to output file
I am reading in a file which consists of scores between two teams. The team that wins gets 2 points, if the teams tie both teams get one point. The result is ranked by points and if there is a tie ...
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Concatenating two IEnumerables with a limit
I've been playing around with generators, generics and extension methods in C# (5.0) and wanted to create an extension method for IEnumerable, which would append ...
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Creating a random code and saving if it does not exist
I have created a script to generate 5 random codes, check if any one of them exists in the database, and if not, insert the record. The script will throw an exception if a single code could not be ...
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Simple generic linq expression generation method
Here is my generic method for creating linq expression based on field name of a type, operator (as enumerations of operators generated from XSD) and value of field
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LINQ sorting using custom IComparer is very slow
Joining a project with some crazy LINQ sorting statements and after refactoring by the team using a custom comparer we found out that it is so slow for some data that you actually think it is an ...
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LINQish command line parser
I needed to parse some command line switches from a string and I tried to do it the easy way so I just wrote this:
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Search for variants of keywords using LINQ
First, I'm adding words entered into a search field to an array. Then, I'm getting results from a stored procedure on SQL Server using Database First approach with Entity Framework.
Finally, for ...
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Linqy Sudoku game generator
I created a class that is able to generate a Sudoku board.
The following board generation steps are made:
Create a valid board with numbers on all squares, row by row
Basically I always generate ...
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Check if an Array of Arrays contains a value in node js
In C#, I could check if any of the nested List collection has a value. Example of such structure Check a List[]> contains a value using Linq
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