title: ggplot function select multiple subset
body: <p>I'm not an expert with the ggplot2 package. I have a subset selection problem.</p>
  
  <p>Here is my code that produce this kind of graph...</p>
  
  <pre><code>  g &lt;- ggplot(merged_data,aes_string(x=Order,fill=var.y)) + 
                 scale_y_continuous(expand = c(0.05,0)) + 
                xlab(paste("Order","Total number of sequences",sep=" - ")) + 
                ggtitle(main.str) +
                geom_bar(position="fill", 
                         subset = .(Order !=  ""), 
                         width=0.6,hjust =0)+
                geom_text(stat="bin",  
                          subset = .(Order !=  ""), 
                          color="black", hjust=1, vjust = 0.5, size=2,
                aes_string(fill=NULL,x = Order,y = "0", label="..count.."))+
                coord_flip()
  </code></pre>
  
  <p>For <code>geom_bar</code> and <code>geom_text</code>  I select subset of data that remove empty names </p>
  
  <pre><code>subset = .(eval(parse(text=var.x)) !=  "")
  </code></pre>
  
  <p>this is a simple example with only 2 bars.
  Here is a the data ...</p>
  
  <pre><code>Collector&lt;- c("BK","YE_LD","BK","JB","JB",
           "BK","BK","BK","JB","YE_LD")
  Order&lt;-c("A","B","B","B","A",
           "B","B","A","B","B")
  data &lt;- data.frame(Order,Collector)
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/Fi7J0.png" alt="enter image description here"></p>
  
  <p>Now I want to add a cutoff to my subset... only show the variable that that have a minimum of counts.</p>
  
  <p>So if I put the cutoff = 4 ... I will get only the bar at the bottom that have 7 counts, the bar at the top with 3 counts should not appear.</p>
  
  <p>I have no idea how I can do this ...
  Thanks for your help.</p>