Hi.

I'm trying to read a list of strings and 'grep' them one by one from a data frame and draw and save the plots using R 'for loop' function. However, I got warning message and nor plots.

"Warning message:
In grep(cpg, colnames(dta)) :
  argument 'pattern' has length > 1 and only the first element will be used"

Here's the code I used,

for (cpg in cpg.list){
      dta1 <- dta[,grep(cpg,colnames(dta))]
      jpeg(paste(files[cpg]), '.jpg', width = 700, height = 500)
      par(mar=c(3,3,3,3))
      stripchart(dta1, method='jitter', vertical=T)
      boxplot(dta1, add = T)
      dev.off()
}

Can someone explain what I did wrong?

Thank you!