itertools — Python Technical Interview Questions & Answers

itertools

itertools

  • itertools is about functions that take/return functions, or itertools helpers (chain, cycle, combinations). map/filter/lambda are the fresher versions.
  • Keep it concrete: map(str.upper, ["a","b"]) → A B. itertools.chain([1],[2,3]) → 1 2 3.
  • itertools — output: [1, 2, 3] then [('A','B'), ('A','C'), ('B','C')].

Technical Interview Tip: One tiny map/filter or itertools line + output.

Code Examples for itertools

Example

# itertools
import itertools
print(list(itertools.chain([1], [2, 3])))
print(list(itertools.combinations("ABC", 2)))

itertools — output: [1, 2, 3] then [('A','B'), ('A','C'), ('B','C')].

How to Explain itertools to an Interviewer

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

itertools works with functions or iterators. map/filter or itertools.

What does the example print, and why?

itertools — output: [1, 2, 3] then [('A','B'), ('A','C'), ('B','C')]

What mistake do freshers make with itertools?

Overusing lambda when def is clearer.