zoukankan      html  css  js  c++  java
  • 特征选择

    Filter methods
    These include simple statistical test to determine if a feature is statistically significant for example the p value for a t test to determine if the null hypothesis should be accepted and the feature rejected. This does not take into account feature interactions and is generally not a very recommended way of doing feature selection as it can lead to lost in information 

     Wrapper based methods

     Tree based models like RandomForest are also robust against issues like multi-collinearity, missing values, outliers etc as well as being able to discover some interactions between features. However this can be rather computationally expensive.

    a simple wrapper method: Forward Feature Selection (FFS) ,特征逐步添加。 每次迭代添加一个特征。

    Feature engineering is a super-set of  activities which include feature extraction, feature construction and feature selection. Each of the three are important steps and none should be ignored. We could make a generalization of the importance though, from my experience the relative importance of the steps would be feature construction > feature extraction > feature selection.

  • 相关阅读:
    velocity导出word报错解决
    Java解析网段下包含的所有IP地址
    ORACLE中的DECODE函数
    td标签内的内容过长导致的问题的解决办法
    android 知识点
    geekNews 学习总结
    android 操蛋的gradle
    rxJava rxandroid 学习
    线程池ThreadPoolExecutor
    j2ee tomcat 部署学习
  • 原文地址:https://www.cnblogs.com/xinping-study/p/8376728.html
Copyright © 2011-2022 走看看