title: ggplot: plot two columns of data frame
body: <p>here is a sample dataset to explain the question:</p>
  
  <pre><code>s &lt;- 
  "F V1  V2  P
  0 0.5 0.7  0
  0 1.5 1.7  1
  1 0.7 0.9  0
  1 1.7 1.9  1
  "
  d &lt;- read.delim(textConnection(s), sep="")
  </code></pre>
  
  <p>I want to plot this data in one plot using <code>ggplot</code> such that:</p>
  
  <ul>
  <li>on x - axis I have <code>P</code></li>
  <li>on Y - axis I have both <code>V1</code> (triangles) and <code>V2</code> (squares)</li>
  <li>points with <code>F</code> = 0 are red and points with <code>F</code> = 1 are blue.</li>
  </ul>
  
  <p>That is, I want to plot two columns on the data frame with different markers such that color of every point is defined by <code>F</code>.</p>
  
  <p>Thanks.</p>
  
  <p>EDIT: I believe it is not duplicate question -- in mentioned answer the data frame is melted. But in my case when I melt, I also lose F column which defines color so that solution doesn't work.</p>