Python Coding challenge - Day 547| What is the output of the following Python Code?

 

Code Explanation:

1. Importing reduce from functools

from functools import reduce

reduce() is used to apply a function cumulatively to items in an iterable (like a list).

It's part of Python's functools module, so you must import it before using.

2. Defining the List

data = [1, 2, 3, 4, 5]

This line defines a list called data containing the numbers from 1 to 5.

This list will be used as the input for the reduce() function.

3. Defining the Function even_sum

def even_sum(acc, x):

    return acc + x if x % 2 == 0 else acc

This function takes two arguments:

acc: the accumulated total so far

x: the current item from the list

It checks if x is even (i.e., x % 2 == 0).

If even, it adds x to acc.

If odd, it returns acc unchanged.

This function is designed to sum only the even numbers in a list.

4. Applying reduce()

result = reduce(even_sum, data, 0)

reduce() will apply the even_sum function across the data list.

It starts with an initial value of 0 (the third argument).

Steps:

acc = 0, x = 1 → 1 is odd → return 0

acc = 0, x = 2 → 2 is even → return 0 + 2 = 2

acc = 2, x = 3 → 3 is odd → return 2

acc = 2, x = 4 → 4 is even → return 2 + 4 = 6

acc = 6, x = 5 → 5 is odd → return 6

Final result is 6 (sum of even numbers: 2 + 4).

5. Printing the Result

print(result)

This prints the final result of the reduction:

6

Final Output:

6

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