[c#] Linq select objects in list where exists IN (A,B,C)

I have a list of orders.
I want to select orders based on a set of order statuses.

So essentially select orders where order.StatusCode in ("A", "B", "C")

// Filter the orders based on the order status
var filteredOrders = from order in orders.Order
                     where order.StatusCode.????????("A", "B", "C")
                     select order;

This question is related to c# linq list linq-to-objects exists

The answer is


NB: this is LINQ to objects, I am not 100% sure if it work in LINQ to entities, and have no time to check it right now. In fact it isn't too difficult to translate it to x in [A, B, C] but you have to check for yourself.

So, instead of Contains as a replacement of the ???? in your code you can use Any which is more LINQ-uish:

// Filter the orders based on the order status
var filteredOrders = from order in orders.Order
                     where new[] { "A", "B", "C" }.Any(s => s == order.StatusCode)
                     select order;

It's the opposite to what you know from SQL this is why it is not so obvious.

Of course, if you prefer fluent syntax here it is:

var filteredOrders = orders.Order.Where(order => new[] {"A", "B", "C"}.Any(s => s == order.StatusCode));

Here we again see one of the LINQ surprises (like Joda-speech which puts select at the end). However it is quite logical in this sense that it checks if at least one of the items (that is any) in a list (set, collection) matches a single value.


Just be careful, .Contains() will match any substring including the string that you do not expect. For eg. new[] { "A", "B", "AA" }.Contains("A") will return you both A and AA which you might not want. I have been bitten by it.

.Any() or .Exists() is safer choice


var statuses = new[] { "A", "B", "C" };

var filteredOrders = from order in orders.Order
                             where statuses.Contains(order.StatusCode)
                             select order;

Try with Contains function;

Determines whether a sequence contains a specified element.

var allowedStatus = new[]{ "A", "B", "C" };
var filteredOrders = orders.Order.Where(o => allowedStatus.Contains(o.StatusCode));

Examples related to c#

How can I convert this one line of ActionScript to C#? Microsoft Advertising SDK doesn't deliverer ads How to use a global array in C#? How to correctly write async method? C# - insert values from file into two arrays Uploading into folder in FTP? Are these methods thread safe? dotnet ef not found in .NET Core 3 HTTP Error 500.30 - ANCM In-Process Start Failure Best way to "push" into C# array

Examples related to linq

Async await in linq select How to resolve Value cannot be null. Parameter name: source in linq? What does Include() do in LINQ? Selecting multiple columns with linq query and lambda expression System.Collections.Generic.List does not contain a definition for 'Select' lambda expression join multiple tables with select and where clause LINQ select one field from list of DTO objects to array The model backing the 'ApplicationDbContext' context has changed since the database was created Check if two lists are equal Why is this error, 'Sequence contains no elements', happening?

Examples related to list

Convert List to Pandas Dataframe Column Python find elements in one list that are not in the other Sorting a list with stream.sorted() in Java Python Loop: List Index Out of Range How to combine two lists in R How do I multiply each element in a list by a number? Save a list to a .txt file The most efficient way to remove first N elements in a list? TypeError: list indices must be integers or slices, not str Parse JSON String into List<string>

Examples related to linq-to-objects

Using LINQ to group a list of objects Linq select objects in list where exists IN (A,B,C) Find() vs. Where().FirstOrDefault() how to query LIST using linq How can I get LINQ to return the object which has the max value for a given property? Remove duplicates in the list using linq Sorting a list using Lambda/Linq to objects Filtering lists using LINQ Dynamic LINQ OrderBy on IEnumerable<T> / IQueryable<T>

Examples related to exists

Select rows which are not present in other table How to fix "Only one expression can be specified in the select list when the subquery is not introduced with EXISTS" error? Check if record exists from controller in Rails sql: check if entry in table A exists in table B How to exclude records with certain values in sql select SQL - IF EXISTS UPDATE ELSE INSERT INTO Linq select objects in list where exists IN (A,B,C) PL/pgSQL checking if a row exists How to Check if value exists in a MySQL database MongoDB: How to query for records where field is null or not set?