What is the difference between __new__ and __init__?
PICTURE THIS: RAG CHATBOT
Simple meaning
__new__ is a static constructor that allocates and returns the instance (or another object).
WHY — OOP instead of guessing?
Why interviewers care about OOP:
contrast on OOP, not two memorised paragraphs.
the developer, then one case where picking wrong hurts.
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:
- 1__new__ is a static
constructor that allocates and returns the instance (or another object).
- 2__init__ then initializes that
instance and must return None.
- 3You override __new__ for
immutable types, singletons, or when you might return a cached instance instead of a new one.
- 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
__new__ is a static constructor that allocates and returns the instance (or another object). __init__ then initializes that instance and must return None.