Reduce
Domain: Programming Fundamentals
🎯 Motivation
Combining all items in a collection into a single value - summing, multiplying, finding the max - is what reduce does.
📋 Concrete Example
from functools import reduce; reduce(lambda a,b: a+b, [1,2,3,4]) gives 10. It folds the list into one number.
🔗 Analogy
Making a smoothie - you put in many fruits (the list), blend them all together (the reducing function), and get one smoothie (the single result).