【机器学习算法应用与学习_3_代码API篇】2.0预处理

悠悠 2023-10-11 09:43 37阅读 0赞

[【机器学习算法应用与学习\_3\_代码API篇】2.0预处理][3_API_2.0]

## 编码 ##

### 独热编码 ###

基于树的算法不需要独热编码。

1.pandas方法

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

from sklearn.datasets import load_iris
    import pandas as pd
    #创建数据集
    data = pd.DataFrame({
            'one':[1,2,3],'two':[2,3,4],'city':[3,4,5]})
    #对city独热编码
    data =pd.get_dummies(data, columns=['city'])
    data

![1253211-20190812194402831-442685602.png][]

2.sklearn方法

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

from sklearn import preprocessing
    enc = preprocessing.OneHotEncoder()
    enc.fit([[0, 0, 3], [1, 1, 0], [0, 2, 1], [1, 0, 2]])    # fit来学习编码
    enc.transform([[0, 1, 3]]).toarray()    # 进行编码

[https://zhuanlan.zhihu.com/p/35287916][https_zhuanlan.zhihu.com_p_35287916]

posted on 2019-08-12 19:18  [everda][] 阅读( ...) 评论( ...) [ 编辑][Link 1] 收藏

转载于:https://www.cnblogs.com/everda/p/11342020.html

[3_API_2.0]: https://www.cnblogs.com/everda/p/11342020.html
[ContractedBlock.gif]: https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif
[ExpandedBlockStart.gif]: https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif
[1253211-20190812194402831-442685602.png]: https://img2018.cnblogs.com/blog/1253211/201908/1253211-20190812194402831-442685602.png
[https_zhuanlan.zhihu.com_p_35287916]: https://zhuanlan.zhihu.com/p/35287916
[everda]: https://www.cnblogs.com/everda/
[Link 1]: https://i.cnblogs.com/EditPosts.aspx?postid=11342020