Lambda Functions in Python — Python Technical Interview Questions & Answers

Lambda Functions in Python

Lambda Functions in Python

  • lambda is a one-line function without a def name. Shape: lambda x: x * x. Useful as a key= in sorted, or a tiny map/filter. square = lambda n: n * n then square(5) is 25. Keep it tiny. If you need two statements, write a normal def. Complex lambda looks clever and reads badly.
  • Viva: “anonymous one-line function”. Then sorted(students, key=lambda s: s["marks"]). Prefer def when the logic has a name worth saying out loud.
  • Lambda Functions in Python — output: 5 then ['Asha', 'Neha', 'Ravi'] (or same lengths stay). add is a tiny function.
  lambda a, b: a + b
         │ (2, 3)
         ▼
         5

Technical Interview Tip: lambda with sorted key idea.

Code Examples for Lambda Functions in Python

Example

# lambda
add = lambda a, b: a + b
print(add(2, 3))
print(sorted(["Neha", "Asha", "Ravi"], key=lambda s: len(s)))

Lambda Functions in Python — output: 5 then ['Asha', 'Neha', 'Ravi'] (or same lengths stay). add is a tiny function.

How to Explain Lambda Functions in Python to an Interviewer

Explain Lambda Functions as if you are teaching a junior — definition, then one tiny script.

Tiny anonymous function. Single expression.

What does the example print, and why?

Lambda Functions in Python — output: 5 then ['Asha', 'Neha', 'Ravi'] (or same lengths stay)

What mistake do freshers make with Lambda Functions?

key= in sorted.