ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
59 lines
645 B
Markdown
59 lines
645 B
Markdown
---
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id: 5e9a093a74c4063ca6f7c15d
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challengeType: 11
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videoId: ovYNhnltVxY
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dashedName: data-cleaning-introduction
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---
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# --description--
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More resources:
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\- [Notebook](https://notebooks.ai/rmotr-curriculum/data-cleaning-rmotr-freecodecamp-fd76fa59)
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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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```
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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
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```
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---
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```
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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
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```
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## --video-solution--
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1
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