setwd("E:/R/Feedback Prediction for Blogs")
w=read.csv("E:/R/Feedback Prediction for Blogs/数据/blogData_test-2012.02.01.00_00.csv",header = F)
nn=c(263:276);for(i in nn)w[,i]=factor(w[,i])


(n=nrow(w));D=281;Z=10
CV=function(n,Z=10,seed=888){
  z=rep(1:Z,ceiling(n/Z))[1:n]
  set.seed(seed);z=sample(z,n)
  mm=list();for (i in 1:Z) mm[[i]]=(1:n)[z==i]
  return(mm)}# 输出Z 个下标集;mm[[i]] 为第i 个下标集i=1 到Z
mm=CV(n,Z) #mm[[i]]

gg=V281~.

library(randomForest)
set.seed(1010);for(i in 1:Z)
{m=mm[[i]];M=mean((w[m,D]-mean(w[m,D]))^2)
a=randomForest(gg,data=w[-m,])
NMSE[i]=mean((w[m,D]-predict(a,w[m,]))^2)/M }



提示错误:Error in NMSE[i] = mean((w[m, D] - predict(a, w[m, ]))^2)/M :
  object 'NMSE' not found