Questions tagged [linq]
Language INtegrated Query (LINQ) is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages.
563
questions
7
votes
3answers
1k 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
votes
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
votes
0answers
82 views
Implement Sudoku using LINQ
WiKi and GitHub.
Sudoku rules are being checked with the following tests:
...
0
votes
0answers
55 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
votes
2answers
143 views
4
votes
1answer
57 views
4
votes
2answers
123 views
Finding which items have at least one common value with other items
I have the following collection :
...
1
vote
1answer
57 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:...
7
votes
3answers
361 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
votes
2answers
86 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
votes
2answers
117 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
votes
1answer
299 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
votes
4answers
1k views
LINQ for generating all possible permutations
Permutate() is supposed to generate all possible permutations of the source sequence:
...
3
votes
1answer
64 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
votes
4answers
929 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
vote
0answers
84 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 ...
16
votes
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
121 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
535 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
244 views
SkipLast of an IEnumerable<T> - Linq Extension
As my answer to this question, I came up with this solution:
...
2
votes
1answer
121 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 ...
2
votes
1answer
53 views
Populating dropdown lists, using SQL vs. using expression trees and reflection
I'm working with a large enterprise SQL Server database with dozens of tables that are used mainly as lookups to populate dropdown lists, etc. These tables all follow the convention of having (table)...
3
votes
1answer
108 views
Non brute force algorithm for Birthday Chocolate
Problem: https://www.hackerrank.com/challenges/the-birthday-bar/problem
Lily has a chocolate bar that she wants to share it with Ron for his birthday. Each of the squares has an integer on it. She ...
3
votes
0answers
28 views
Configure multiple application features by common criteria
My FeatureSerivce provides only basic APIs, so it is good in dealing with single features. Like I can configure only one feauture at a time:
...
2
votes
2answers
40 views
LINQ queries to generate a report on accrued work time on projects
The following code fetches data from a MySql database to generate a simple report on accrued work time on projects.
I've been away from Entity Framework for a while and looking at this code you can ...
0
votes
2answers
130 views
Poker Hand evaluation
I want to evaluate Poker Hands an wrote the following Code:
https://dotnetfiddle.net/mxMvq9
Anything wrong / to imporve?
...
6
votes
5answers
220 views
Take N elements from List of Lists
I've come with a solution super tricky for a simple requirement. I think I could solve the problem using LinQ, but I'm not seeing it so clearly at all.
What's sure, I'm not comfortable with my code.
...
3
votes
2answers
176 views
2
votes
1answer
71 views
Parse through an XDocument efficiently and match values to matching object
Minimum viable test program:
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0
votes
1answer
126 views
LINQ or Lambda for two foreach query [closed]
I have a Document Name Table in my SQL database and Files in the Content folder.
I have two lists: ListOfFileNamesSavedInTheDB and ...
4
votes
2answers
121 views
Making a list of customers who buy the top N items from a supplier
I have a method that works perfectly well and does what it's supposed to, albeit a little slow (30 - 40 seconds). I would like to be able to speed it up or at least make it more efficient, any ideas ...
3
votes
1answer
159 views
Logging inside a Linq fluent chain [closed]
I've posted this to Stack Overflow, but someone voted to close as they felt it was opinion based, so I'm bringing it over to Code Review.
I have some Linq fluent chains to shape an original ...
1
vote
2answers
327 views
Using IQueryable.GroupBy to count related database entities
Given a DbSet<Client> from an Entity Framework 6 DbContext, I need to count the number of related ...
-2
votes
1answer
732 views
Filtering List data using LINQ [closed]
In this code I have declared myPushData, myPushDataFilterd and myPushDataFilterd2 variables ...
11
votes
1answer
1k views
Linq for ObservableCollection
Purpose
ObservableCollection<T> is not strictly a WPF class, but its intended purpose seems to be for use in WPF. It's the standard implementation of ...
3
votes
5answers
669 views
Finding Isogram Word
An isogram (also known as a "nonpattern word") is a word or phrase without a repeating letter, however spaces and hyphens are allowed to appear multiple times.
The ...
5
votes
2answers
865 views
Going from IQueryable<IEnumerable<myObj>> to IEnumerable<myObj>
I have a "GetPersonsPerDepartment()" method returning a IQueryable<IEnumerable<Person>> while I'm trying to get a simple ...
1
vote
1answer
933 views
8
votes
4answers
965 views
Custom implementation of the linq Zip operator for different length lists
Based on my answer I have my implementation of linq Zip operator which operates on different length lists, and loops shortest list.
My implementation:
...
-2
votes
1answer
260 views
Method to populate a dictionary from properties
I have a class with some properties. In the class I have a method that is "collecting" all the properties in a specific instance of the class to a dictionary, with the properties name being the ...
-2
votes
1answer
695 views
Reuse Select Expression in LINQ
I have three methods to get the user details based on attributes:
Find user details by id,
Find user details by username,
Find user details by email
Here is the program class:
...
2
votes
3answers
199 views
Grouping report data by one of two criteria
I have a report with a group by filter. A stored procedure returns all the data and maps it to IEnumerable<EventListRow>. The code should then group the data ...
3
votes
2answers
1k views
Get attribute values with LINQ to XML
I'm pulling the values from the following XML based on the attribute name.
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3
votes
1answer
76 views
Determining if there is data left after fetching a page of data
I just faced a problem where I needed to know if extra data was present in a given collection after a Take operation took place. Specifically, this is related to ...
0
votes
1answer
187 views
Sorting table using multiple columns [closed]
I want to sort entries in a given list on Entry column in most efficient way. Here is how my entries look:
...
5
votes
4answers
773 views
Take a desired string, iterate through objects to see if it exists in a given field and append a number until a unique string is found
I wanted to in the most generic way possible write a method in C# to achieve the following.
Take in a string, a set of objects, and a function to access the field of a given object
Look at all of the ...
2
votes
1answer
134 views
Handling related generic type parameters
In answering a question on StackOverflow, it occurred to me that a more generic version of GroupBy for C# that delegated membership in each group to a class could ...
4
votes
4answers
180 views
Add dash between more than two consecutive numbers and comma between other numbers in array
I have an ordered array of integer values: 10, 11, 12, 13, 15, 16, 19
and I need to write a dash between first and last consecutive values when there are more than two consecutive values (10-13). ...
2
votes
0answers
210 views
Handler for jQuery DataTable search with filters and pagination
This AjaxCompound is invoked every time when the user types a key for search or click to sort. It contains 1million data 10 distinct rows by compound name. It takes 1.1 minutes and return only 1-5 KB ...
4
votes
2answers
158 views
EnumerableHelpers: a partial implementation of LINQ for .NET Framework 2.0
Here is a static class with some helper methods for some common LINQ operations on enumerables, built against .NET Framework 2.0. This class is part of the xofz.Core98 library.
Edit: a full review ...
