What does SelectMany flatten?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
It projects each element to a sequence and flattens the results into one sequence.
WHY — LINQ instead of guessing?
Why interviewers care about LINQ:
who only read docs from people who shipped.
and tied to .NET work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1It projects each element
to a sequence and flattens the results into one sequence.
- 2Nested lists become a
single list.
- 3I use it for
child collections.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
It projects each element to a sequence and flattens the results into one sequence. Nested lists become a single list.