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转自：https://yoyoyohamapi.gitbooks.io/mit-ml/content/%E7%89%B9%E5%BE%81%E9%99%8D%E7%BB%B4/articles/PCA.html https://www.jianshu.com/p/162bb4ea1b7f 1.有什么 阅读全文
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"Let's C" is a popular and fun programming contest hosted by the College of Computer Science and Technology, Zhejiang University. Since the idea of th 阅读全文
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The Japanese language is notorious for its sentence ending particles. Personal preference of such particles can be considered as a reflection of the s 阅读全文
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1.R中NA,NaN,Inf代表什么？ NA：缺失数据 NaN：无意义的数，比如sqrt(-2) Inf：正无穷大 -Inf:负无穷大 判断是否存在nan值 is.na(x)#是否存在nan anyNA(x) sum(is.na(x))#存在几个nan值 2.确定一个数值型vector的第一个最值（ 阅读全文