CODEWITHSUNDEEP
linq
doorman
doorman

Reputation: 16959

Using except operator with property condition

I have two lists with different objects. Both objects have a string property name that I need for comparing.

I need to know what values in list A are not contained in list B based on the name property.

Would the except operator work for this case? What would be a optimal way to achive this in Linq?

Upvotes: 1

Views: 26

Answers (1)

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 727047

Except operator removes items based on object equality. Although you could shoehorn your scenario into Except by passing an "equality comparer" that pays attention only to Name property, the resultant code would be hard to understand.

A better approach is to make a set of names that you wish to exclude, and use that set in your query:

var excludedNames = new HashSet<string>(listB.Select(item => item.Name));
var result = listA.Where(item => !excludedNames.Contains(item.Name)).ToList();

Upvotes: 1

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