freeCodeCamp/curriculum/challenges/chinese/08-data-analysis-with-python/data-analysis-with-python-c.../data-cleaning-introduction.md

63 lines
637 B
Markdown

---
id: 5e9a093a74c4063ca6f7c15d
challengeType: 11
videoId: ovYNhnltVxY
---
# --description--
More resources:
\- [Notebook](https://notebooks.ai/rmotr-curriculum/data-cleaning-rmotr-freecodecamp-fd76fa59)
# --question--
## --text--
What will the following code print out?
```py
import pandas as pd
import numpy as np
s = pd.Series(['a', 3, np.nan, 1, np.nan])
print(s.notnull().sum())
```
## --answers--
3
---
```
0 True
1 True
2 False
3 True
4 False
dtype: bool
```
---
```
0 False
1 False
2 True
3 False
4 True
dtype: bool
```
## --video-solution--
1
# --hints--
# --solutions--