What Are Closures In Python?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of Python conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
Python closures are function objects return ed by another function. We use them to eliminate code redundancy.
In the example below, we've written a simple closure for multiplying numbers.
def multiply_number(num):
def product(number):
'product() here is a closure'
return num * number
return product
num_2 = multiply_number(2)
print(num_2(11))
print(num_2(24))
num_6 = multiply_number(6)
print(num_6(1))
The output is:
22
48
6
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.