Back to Freecodecamp

Data Cleaning with DataFrames

curriculum/challenges/english/blocks/data-analysis-with-python-course/5e9a093a74c4063ca6f7c15e.md

latest999 B
Original Source

--description--

Instead of using notebooks.ai like it shows in the video, you can use Google Colab instead.

More resources:

  • <a href="https://github.com/ine-rmotr-curriculum/data-cleaning-rmotr-freecodecamp" target="_blank" rel="noopener noreferrer nofollow">Notebooks on GitHub</a>
  • <a href="https://colab.research.google.com/github/googlecolab/colabtools/blob/master/notebooks/colab-github-demo.ipynb" target="_blank" rel="noopener noreferrer nofollow">How to open Notebooks from GitHub using Google Colab.</a>

--questions--

--text--

What will the following code print out?

py
import pandas as pd
import numpy as np

s = pd.Series([np.nan, 1, 2, np.nan, 3])
s = s.fillna(method='ffill')

print(s)

--answers--

<pre> 0 1.0 1 1.0 2 2.0 3 3.0 4 3.0 dtype: float64 </pre>
<pre> 0 NaN 1 1.0 2 2.0 3 2.0 4 3.0 dtype: float64 </pre>
<pre> 0 NaN 1 1.0 2 2.0 3 NaN 4 3.0 dtype: float64 </pre>

--video-solution--

2