simple script help

HI,


I have subsetted a list of exons and put them in a vector exon_list
 > exon_list=levels(test5$V1)

 I want to loop using that vector to create a big pdf which will contain 
all my barplots  and doing this I got only the last  element in my 
exon_list plotted rather than all of them, I guess this is a silly 
newbie mistake, could any of you help?
another point, how to put a numerical scale on X axis in barplot?

 > for (i in exon_list){
+ pdf(file="test.pdf", width=30, height=30, pointsize=36)
+ barplot(uniq5[ which(uniq5$V1==i), ]$V5, main=i)
+
+ dev.off()
+
+
+ }

thanks a lot
Nathalie

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