Question

I’m new to R, so please bear with me… I managed to load a data frame, and the header has columns such “data$x.y.1” and “data$x.y.2”. I want to programmatically generate the column names to extract each column and plot a histogram. In short, I want to construct ‘data$x.y’ + n, where I’m going to iterate over n. I tried cat and got:

as.name(cat("data$x.y", i, sep="."))
data$x.y.1Error in as.name(cat("data$x.y", i, sep = ".")) : 
invalid type/length (symbol/0) in vector allocation

Answer 1

names(data)

should get your column names

if you want a histogram for each column of data

for(i in names(data)){
  png(paste(i,'.png',sep=""))
  hist(data[,which(names(data)==i)],
       main=paste(i,"some other stuff"),
       xlab=paste(i,"some more stuff") 
      )
  dev.off()
}

That will plant a bunch of .png files with names like x.y.1.png in your working directory.