Python Coding challenge - Day 828| What is the output of the following Python Code?

 

Code Explanation:

Importing reduce from functools

from functools import reduce

The reduce() function applies a binary function (a function that takes two arguments) cumulatively to the items of a sequence.

In simple words: it reduces a list to a single value by repeatedly combining its elements.

Example: reduce(lambda a, b: a + b, [1, 2, 3]) → ((1+2)+3) → 6.

Importing the operator module

import operator

The operator module provides function equivalents of built-in arithmetic operators.

For example:

operator.add(a, b) → same as a + b

operator.mul(a, b) → same as a * b

operator.pow(a, b) → same as a ** b

This makes code cleaner when passing operator functions into higher-order functions like reduce().

Creating a list of numbers

nums = [3, 5, 2]

Here, we define a list named nums containing three integers: 3, 5, and 2.

This list will be used for performing calculations later.

Using list comprehension to square each number

[n**2 for n in nums]

This creates a new list by squaring every element of nums.

3**2 = 9

5**2 = 25

2**2 = 4

So the resulting list becomes: [9, 25, 4].

Reducing (adding) all squared values

res = reduce(operator.add, [n**2 for n in nums])

This line adds all squared numbers using reduce() and operator.add.

The reduce process works like this:

Step 1: operator.add(9, 25) → 34

Step 2: operator.add(34, 4) → 38

The final result stored in res is 38.

Printing the remainder of division

print(res % len(nums))

len(nums) → number of elements in the list → 3.

res % len(nums) → remainder when 38 is divided by 3.

38 ÷ 3 = 12 remainder 2.

So the output is 2.

Final Output

2

600 Days Python Coding Challenges with Explanation