LINQ Interview Question #70
What does Except do in LINQ?
Joins, Grouping, Set & Quantifier Operators Mid-Level Intermediate
Quick Interview Answer
Except returns distinct elements from the first sequence that do not appear in the second sequence. It is a set-difference operation.
Detailed Explanation
Except returns distinct elements from the first sequence that do not appear in the second sequence. It is a set-difference operation.
The direction matters: first.Except(second) is not generally the same as second.Except(first).
Code Example
var existing = new[] { 1, 2, 3, 4 };
var removed = new[] { 2, 4 };
var remaining = existing.Except(removed);
// 1, 3