Python Coding challenge - Day 566| What is the output of the following Python Code?

 

Code Explanation:

1. Importing reduce Function

from functools import reduce

The reduce() function is part of the functools module in Python.

reduce() applies a function cumulatively to the items of an iterable (like a list), from left to right, reducing the iterable to a single value.

Example: reduce(lambda x, y: x + y, [1, 2, 3]) results in ((1 + 2) + 3) = 6.

2. Defining the List

nums = [1, 2, 3, 4]

This creates a list named nums containing four integers: [1, 2, 3, 4].

3. Applying reduce with a Lambda Function

res = reduce(lambda acc, x: acc - x, nums)

reduce() will use the lambda function to combine all elements of nums one by one.

The lambda function: lambda acc, x: acc - x takes two arguments:

acc is the accumulated result so far

x is the current item in the list

Step-by-step Breakdown:

Starting with the first two elements:

Step 1: acc = 1, x = 2 → 1 - 2 = -1

Step 2: acc = -1, x = 3 → -1 - 3 = -4

Step 3: acc = -4, x = 4 → -4 - 4 = -8

Final result: res = -8

4. Printing the Result

print(res)

This outputs the final reduced result to the console:

Final Output

-8

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