--- id: 5e9a093a74c4063ca6f7c15e title: Data Cleaning with DataFrames challengeType: 11 videoId: sTMN_pdI6S0 dashedName: data-cleaning-with-dataframes --- # --description-- *Instead of using notebooks.ai like it shows in the video, you can use Google Colab instead.* More resources: - [Notebooks on GitHub](https://github.com/ine-rmotr-curriculum/data-cleaning-rmotr-freecodecamp) - [How to open Notebooks from GitHub using Google Colab.](https://colab.research.google.com/github/googlecolab/colabtools/blob/master/notebooks/colab-github-demo.ipynb) # --question-- ## --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--
0 1.0 1 1.0 2 2.0 3 3.0 4 3.0 dtype: float64---
0 NaN 1 1.0 2 2.0 3 2.0 4 3.0 dtype: float64---
0 NaN 1 1.0 2 2.0 3 NaN 4 3.0 dtype: float64## --video-solution-- 2