Python Coding challenge - Day 1181| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Importing accumulate

from itertools import accumulate

✅ Explanation:

accumulate() is imported from Python's itertools module.

It calculates running totals (cumulative sums).

Instead of returning the final sum only, it returns the sum at every step.

Think of it as:

1

1+2

1+2+3

1+2+3+4

🔹 2. Creating a List

nums = [1, 2, 3, 4]

✅ Explanation:

A list named nums is created.

Contents:

[1, 2, 3, 4]

🔹 3. Calling accumulate()

accumulate(nums)

✅ Explanation:

Python creates an iterator that produces cumulative sums.

It does NOT immediately create a list.

Internally:

Running Sum

will be calculated step by step.

🔹 4. First Element

Current value:

1

Running total:

1

Output produced:

1

🔹 5. Second Element

Current value:

2

Running total:

1 + 2 = 3

Output produced:

3

🔹 6. Third Element

Current value:

3

Running total:

3 + 3 = 6

Output produced:

6

🔹 7. Fourth Element

Current value:

4

Running total:

6 + 4 = 10

Output produced:

10

🔹 8. Converting to List

list(accumulate(nums))

✅ Explanation:

The iterator values are collected into a list.

Generated values:

1

3

6

10

List becomes:

[1, 3, 6, 10]

🔹 9. Printing Result

print(list(accumulate(nums)))

Prints:

[1, 3, 6, 10]

🎯 Final Output

[1, 3, 6, 10]

Book: 

500 Days Python Coding Challenges with Explanation