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Questions - linq

Select fields in a matching array and parent with C# Linq

I have an object that I need to get some fields from just the first one matched. The key thing is "prices" will either be sorted in ascending or descending "base" order. Find the...
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slabsken

c#

linq

Votes: 0

Answers: 3

Latest Answer

It's not clear to me what your selection criteria are, but here's how I'd think about this query. First, select the leaf nodes since you do your filtering based on them. Here, I make an assumption abo...
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Eric J.

Lambda Expression for FirstOrDefault with two parameters

I have a lambda expression that is passed to a First() or FirstOrDefault() call. I would like to dynamically inject a parameter value into the lambda when it is executed. This is the hacked code I hav...
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lkujala

c#

linq

Votes: 0

Answers: 1

Latest Answer

You can call your Lambda function this way. public GetRow() { T currentRow = CompareRow; var firstRow = Rows.First(row => Lambda(row, CompareRow)); // get first row that matches Lambda ...
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Steve Wong

Counting active listings by month and year

I am currently working with real-estate data, and each Listing entity has a ListingDate and a CloseDate. What I am currently trying to do is to count how many Listings are active in a given month and ...
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Shawn

c#

.net

entity-framework

linq

Votes: 0

Answers: 2

Latest Answer

Let's assume that date is given in DateTime structs. (You can parse text input to DateTime, check this) We can iterate over a List containing Listing entities, and perform a check to see if given date...
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fyb

Parallel.Invoke and Index was outside the bounds of the array

I am sporadically seeing the following error, System.IndexOutOfRangeException: Index was outside the bounds of the array. at System.Collections.Generic.List`1.Add(T item) I have a console applicatio...
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JGV

c#

multithreading

linq

thread-safety

generic-list

Votes: 0

Answers: 2

Latest Answer

The fundamental issue is that List<T>.Add is not thread safe. By trying to add to the same array in parallel, you are most likely causing an internal collision, potentially during resizing opera...
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David L

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