setwd("D:/data") #设定工作路径
d4.1<-read.csv("C:\\Users\\86167\\Desktop\\新建 XLSX 工作表 (6).csv", header=T)
d<-dist(d4.1, method="euclidean", diag=T, upper=F, p=2) 

## Warning in dist(d4.1, method = "euclidean", diag = T, upper = F, p = 2):
## 强制改变过程中产生了NA

HC<-hclust(d, method="single")
plot(HC, hang=-1)
abline(h=22) 
abline(h=10)

HC1<-hclust(d,method="complete") #采用最大距离法聚类
plot(HC1,hang=-1) #绘制最大距离法聚类树状图
rect.hclust(HC1,k=3,border="red")