数据挖掘作业

一:用R语言编程实现P56页19题

以19(2)为例编写R语言程序，其他小题程序类似1.余弦相似度

> x=c(0,1,0,1)

> y=c(1,0,1,0)

> xy=sum(x*y)

> x1=sqrt(sum(x^2))

> y1=sqrt(sum(y^2))

> c=xy/(x1*y1)

> c

[1] 0

2.相关性

> x=c(0,1,0,1)

> y=c(1,0,1,0)

> xbar=mean(x)

> ybar=mean(y)

> len=length(x)

> sx=sqrt((1/(len-1))*sum((x-xbar)^2))

> sy=sqrt((1/(len-1))*sum((y-ybar)^2))

> sxy=(1/(len-1))*sum((x-xbar)*(y-ybar))

> corrxy=sxy/(sx*sy)

> corrxy

3.欧几里得距离

> x=c(0,1,0,1)

> y=c(1,0,1,0)

> dxy=sqrt(sum((x-y)^2)) > dxy

[1] 2

4.Jaccard系数

> x=c(0,1,0,1)

> y=c(1,0,1,0)

> f00=f01=f10=f11=0

> len=length(x)

> j=1

> while(j

+ {if(x[j]==0&y[j]==0) + f00=f00+1

+ if(x[j]==0&y[j]==1)

+ f01=f01+1

+ if(x[j]==1&y[j]==0)

+ f10=f10+1

+ if(x[j]==1&y[j]==1)

+ f11=f11+1

> Jaccard=f11/(f10+f01+f11)

> Jaccard

[1] 0

其他小题运算结果：

（1）c= 1; corr=NaN;dxy=2

（2）c=0;corr=-1;dxy=2;Jaccard=0 （3）c=0;corr=0;dxy=2

（4）c=0.75;corr=0.25;Jaccard=0.6 （5）c=0;corr= -1.433292e-17

二．学习数据导入方法

1.导入文本文件

> a<-read.table("e:/R/r1.txt")

> a

V1 V2 V3 V4

1 16.85 12.35 42.3

2 0.37

2 22.00 15.30 46.51 0.76

3 8.97 7.98 30.36 0.17

4 10.2

5 8.99 40.44 0.46

5 20.81 20.00 35.87 0.43

2.导入excel数据

> b<-read.table("e:/R/r2.csv")

> b

V1

1 16.85,12.35,42.32,0.37

2 22,15.3,46.51,0.76

3 8.97,7.98,30.36,0.17

4 10.25,8.99,40.44,0.46

5 20.81,20,35.87,0.43

3.导入spss数据

> library(Hmisc)

> c<-spss.get("e:/R/r3.sav")

警告信息：

In read.spss(file, bels = bels, to.data.frame = to.data.frame, :

e:/R/r3.sav: Unrecognized record type 7, subtype 18 encountered in system file

> c

VAR00001 VAR00002 VAR00003 VAR00004

1 16.85 12.35 42.3

2 0.37

2 22.00 15.30 46.51 0.76

3 8.97 7.98 30.36 0.17

4 10.2

5 8.99 40.44 0.46

5 20.81 20.00 35.87 0.43