Python Coding challenge - Day 1196| What is the output of the following Python Code?

 

Code:

from functools import reduce nums = [1, 2, 3, 4] result = reduce( lambda x, y: x * y, nums ) print(result)

Explanation:

🔹 1. Importing reduce

from functools import reduce

✅ Explanation

reduce() is imported from Python's functools module.

It is used to reduce an entire iterable (list, tuple, etc.) into a single value.

It repeatedly applies a function to two values until only one value remains.

Think of reduce() like a machine that combines many values into one final result.

1   2   3   4

│   │   │   │

└──► Combine ◄──┘

        │

        ▼

One Final Answer

🔹 2. Creating the List

nums = [1, 2, 3, 4]

✅ Explanation

A list named nums is created.

Current list:

[1, 2, 3, 4]

Memory:

nums

 │

 ▼

[1, 2, 3, 4]

🔹 3. Calling reduce()

result = reduce(

✅ Explanation

reduce() starts processing the list.

Syntax:

reduce(function, iterable)

Here,

Function → lambda x, y: x * y

Iterable → nums

Its goal is to multiply all numbers and return one final value.

🔹 4. Understanding the Lambda Function

lambda x, y: x * y

✅ Explanation

This anonymous function takes two values and returns their product.

Equivalent normal function:

def multiply(x, y):

    return x * y

Every time reduce() needs to combine two values, it calls this function.

🔹 5. First Iteration

Initially:

[1, 2, 3, 4]

Python picks the first two values.

x = 1

y = 2

Calculation:

1 * 2

Result:

2

Now Python replaces 1 and 2 with the result.

Remaining calculation becomes:

2, 3, 4

Visual:

1 × 2

↓

2

New Sequence

[2,3,4]

🔹 6. Second Iteration

Current sequence:

[2,3,4]

Python picks:

x = 2

y = 3

Calculation:

2 * 3

Result:

6

Updated sequence:

[6,4]

Visual:

2 × 3

↓

6

New Sequence

[6,4]

🔹 7. Third Iteration

Current sequence:

[6,4]

Python picks:

x = 6

y = 4

Calculation:

6 * 4

Result:

24

Only one value remains.

Final result:

24

Visual:

6 × 4

↓

24

🔹 8. Storing the Result

result = 24

Current memory:

result

↓

24

🔹 9. Printing the Result

print(result)

✅ Explanation

Python prints the final value stored in result.

Output:

24

🎯 Final Output

24