title: How to show null data in barplot R
body: <p>I want to draw a barplot with in axis x the number of months and in axis y the value of a variable. The variable can be null for some months. How can I coerce the axis x to always show the 12 months?</p>
  
  <p>With V a data frame like:</p>
  
  <pre><code>    month variable
      1  125
      2  45 
      3  158
      4  15
      5  58
      6  78
      7  89
      9  15
      10 85
      11 799
      12 55
  </code></pre>
  
  <p>Here in August (month 8) the variable is 0.</p>
  
  <pre><code>bp &lt;- barplot(V[,2],  axes = FALSE)
  axis(1, at = bp, labels=c("jan", "feb", "mar", "apr", "may", "jun", "jul", "aug", "sep", "oct", "nov", "dec"))
  </code></pre>
  
  <p>Thanks</p>