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63 lines
1.1 KiB
Markdown
63 lines
1.1 KiB
Markdown
---
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id: 5e9a093a74c4063ca6f7c15d
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title: Data Cleaning Introduction
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challengeType: 11
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videoId: ovYNhnltVxY
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bilibiliIds:
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aid: 250574398
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bvid: BV1Pv411A7GN
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cid: 409018611
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dashedName: data-cleaning-introduction
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---
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# --description--
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*Instead of using notebooks.ai like it shows in the video, you can use Google Colab instead.*
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More resources:
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- <a href="https://github.com/ine-rmotr-curriculum/data-cleaning-rmotr-freecodecamp" target="_blank" rel="noopener noreferrer nofollow">Notebooks on GitHub</a>
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- <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>
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# --question--
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## --text--
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What will the following code print out?
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```py
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import pandas as pd
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import numpy as np
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s = pd.Series(['a', 3, np.nan, 1, np.nan])
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print(s.notnull().sum())
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```
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## --answers--
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3
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---
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<pre>0 True
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1 True
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2 False
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3 True
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4 False
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dtype: bool</pre>
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---
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<pre>0 False
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1 False
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2 True
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3 False
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4 True
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dtype: bool</pre>
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## --video-solution--
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1
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