title: read several csv files and same graphs for each csv in one plot
body: <p>I have a list of 12 csv files in one directory and I want to plot one of the colum in function of an other one, for each csv files and the 12 graphs should appear and save in one file. 
  I have tried the following code that works for one csv file, but as soon as I set up the loop to read each file, it doesn't work.</p>
  
  <pre><code>library(lattice)
  fichiers &lt;- list.files(wd_envt_travail3, pattern=".csv")  
  # wd_envt_travail3 = path where the files are
  
  numfiles &lt;- length(fichiers) 
  df &lt;- data.frame()
  
  # i=2: test
  
  # Reading of all the files
  for(i in 1:numfiles){
     xx &lt;- read.csv(as.character(fichiers[i]),sep=";")
     df &lt;- rbind(df, xx)  
     xyplot(df$hauteur_epi_2 ~ df$hauteur_epi_1, df, xlim=c(0,15),ylim=c(0,15))
  }
  </code></pre>
  
  <p>Any suggestions would be appreciated.
  Thank you very much in advance</p>