Custom LINQ Operator?

Short answer: public static class LinqExtensions { public static IEnumerable<T> WhereNot<T>(this IEnumerable<T> source, Func<T,bool> predicate) { foreach (var item in source) if (!predicate(item)) yield return item; } } Usage var employees = list.WhereNot(e => e.IsDeleted);

Example code

public static class LinqExtensions
{
public static IEnumerable<T> WhereNot<T>(this IEnumerable<T> source, Func<T,bool> predicate) {
foreach (var item in source)
if (!predicate(item)) yield return item; }
} Usage var employees = list.WhereNot(e => e.IsDeleted);

Real-world example (ShopNest)

Answer with: definition → one ShopNest-style story → trade-off → how you would verify it in production.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.