title: How to create grouped barplot with R
body: <p>I am trying to create  grouped bar plot with R. I tried the following code to create a simple barplot.</p>
  
  <pre><code>x=c(99,9,104,67,86,53,83,29,127,31,179,86,74,80,100,150,68,18,81,47)
  names(x)= c("A","C","E","D","G","F","I","H","K","M","L","N","Q","P","S","R","T","W","V","Y") 
      barplot(x)
  y= c(105673,18140,92426,76776,93974,53470,75155,30700,77847,28863,124602,55703,
  50160,60685,78693,69581,70846,18285,92789,45728)
  names(y)= c("A","C","E","D","G","F","I","H","K","M","L","N","Q","P","S","R","T","W","V","Y") 
  barplot(y)
  </code></pre>
  
  <p>I have to combine the above two  bar plots. I can't figure out how to combine them.</p>
  
  <p>I tried with gplot.</p>
  
  <pre><code>require(ggplot2)
  data(mydata)
  head(mydata)
  ggplot(mydata, aes(aminoacid, fill=cut)) + geom_bar(position="dodge") +
  opts(title="aminoacid analysis ")
  
  Error in data.frame(x = c(2L, 3L, 5L, 4L, 7L, 6L, 9L, 8L, 10L, 12L, 11L,  :  
  
  arguments imply differing number of rows: 21, 228
  </code></pre>
  
  <p>I tried the following code also.</p>
  
  <pre><code>counts &lt;- table(mydata)
  barplot(counts, main="amino acid analysis",`xlab="aminoacid codes", col=c("darkblue","red")`legend = rownames(counts), beside=TRUE))
  
  Error in barplot.default(counts, main = "aminoacid analysis",  :
  'height' must be a vector or a matrix   
  </code></pre>
  
  <p>How can I solve these errors?</p>
  
  <p>Please help me to create  a grouped barplot with R.</p>