R数组置换命名列和行

Question

This is a follow up question to convert 4-dimensional array to 2-dimensional data set in R which was answered by @Ben-Bolker.

I have a 3D array called 'y' with dimensions [37,29,2635] (ie firms, years, class). Using Ben's formula:

avm11<-matrix(aperm(y,c(1,3,2)),prod(dim(y)[c(1,3)]))

I managed to convert it to a 2D array with dimensions [37*2635,29]. However, the row names have become meaningless numbers and I'd need to generate row names during the permutation so that I'd get 97495 unique row names of the type firm_class.

I've been trying to do so via paste0() but I'm doing something wrong. Any suggestions?

Answer 1

You could use seq_len() for this. Eg

rownames(avm11)<-paste(seq_len(length(avm11[,1])),"observation",sep=" ")

To make the rownames dependable on the variable firm_class:

#Create data frame:
df<-data.frame(X=c(0,1,2,3,4,5),Y=c("a","b","c","d","e","f"))
n<-length(df[,1])

#Generate names containing class name and unique number:
namevector<-sapply(seq_len(n),function(i) names_vector[i]<-paste("Class", df[i,1], i,sep="."))

#Equate rownames to generated names:
rownames(df)<-namevector