Python Coding challenge - Day 672| What is the output of the following Python Code?

 Code Explanation:

1. Importing Pandas

import pandas as pd

Loads the pandas library and assigns it the alias pd.

This lets us use pandas objects like Series and functions like rolling() and mean().

2. Creating a Series

s = pd.Series([1, 2, 3, 4, 5])

pd.Series() creates a 1D labeled array.

Here, the values are [1, 2, 3, 4, 5].

Default index is [0, 1, 2, 3, 4].

So the Series looks like:

0    1

1    2

2    3

3    4

4    5

dtype: int64

3. Rolling Window Operation

s.rolling(2)

.rolling(2) creates a rolling (or moving) window of size 2.

It means pandas will look at 2 consecutive values at a time.

For our Series [1, 2, 3, 4, 5], the rolling windows are:

Window 1: [1, 2]

Window 2: [2, 3]

Window 3: [3, 4]

Window 4: [4, 5]

Important: The very first element (1) has no previous element to pair with (since window size = 2), so its result will be NaN.

4. Taking the Mean

s.rolling(2).mean()

Calculates the mean (average) for each window:

Window Values Mean

[1] Not enough values → NaN

[1, 2] (1+2)/2 = 1.5

[2, 3] (2+3)/2 = 2.5

[3, 4] (3+4)/2 = 3.5

[4, 5] (4+5)/2 = 4.5

So the result is:

0    NaN

1    1.5

2    2.5

3    3.5

4    4.5

dtype: float64

5. Converting to List

.tolist()

Converts the pandas Series into a normal Python list.

Final list:

[nan, 1.5, 2.5, 3.5, 4.5]

Final Output:

[nan, 1.5, 2.5, 3.5, 4.5]

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