How I can count variable occurrence in R Language

Question

For simulated data I want to find VIF. I also want to know that at different iterations how many times a variable appeared to have VIF >10.

    for (i in 1:10){
     z1<-rnorm(1000,0,1)
     z2<-rnorm(1000,0,1)
     z3<-rnorm(1000,0,1)

          x1<-z1
          x2<-z1*2+z2
          x3<-z2+z3
          X<-cbind(x1,x2,x3)
          sx<-scale(X)/sqrt(999)

      for(v in 1:ncol(X)){
          R2<-summary(lm(X[,v]~X[,-v]))$r.squared  
          vif<-1/(1-R2)
          if(vif>10) 
            cname<-as.data.frame(colnames(X)[v])
            table(cname)
      }
    }

Thanks in advance

Where does `X` come from and where is the simulation? Please make this reproducible. — Roland, May 25 '13 at 10:13
Please help us help you by providing us with a reproducible example (i.e. code and example data), see http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example for details. — Paul Hiemstra, May 25 '13 at 10:16

score 1 · Accepted Answer · answered May 25 '13 at 10:37

If I understood correctly, you need this one.

set.seed(12345)
SimNo <- 10
mat <- matrix(data=NA, nrow=SimNo, ncol=3, byrow=TRUE)
for (i in 1:SimNo){
     z1<-rnorm(1000,0,1)
     z2<-rnorm(1000,0,1)
     z3<-rnorm(1000,0,1)

          x1<-z1
          x2<-z1*2+z2
          x3<-z2+z3
          X<-cbind(x1,x2,x3)
          sx<-scale(X)/sqrt(999)

      for(v in 1:ncol(X)){
          R2<-summary(lm(X[,v]~X[,-v]))$r.squared
          vif<-1/(1-R2)
          if(vif>10) mat[i, v] <- 1 else mat[i, v] <- 0
      }
    }
mat



      [,1] [,2] [,3]
 [1,]    0    1    0
 [2,]    0    0    0
 [3,]    0    1    0
 [4,]    0    1    0
 [5,]    0    0    0
 [6,]    0    0    0
 [7,]    0    0    0
 [8,]    0    1    0
 [9,]    0    1    0
[10,]    0    1    0

colSums(mat)

[1] 0 6 0

Thanks for your help. I it be improved by having variable names as header. such as x1 x2 x3 // 0 6 0. — itfeature.com, May 25 '13 at 10:47
@itfeature.com if this answer helps to figure out you problem, consider it as right answer by checking the tick symbol. Thanks — MYaseen208, May 25 '13 at 10:54

How I can count variable occurrence in R Language

1 Answers1