title: ggplot and R: Two variables over time
body: <p>I'd like to know how to make it so that x and y, in the following example data set are plotted on the vertical axis for each element of frame in the horizontal axis. How do I do this with ggplot2?</p>
  
  <p>x, y = variables, frame = YYYYMM</p>
  
  <p>Example Data: </p>
  
  <pre><code>df &lt;- structure(list(x = c(0.000892333625290767, 0.0161153931761482, 
  0.0188150880795816, 0.0268699106638318, 0.018657330651898, 0.0101065034206662, 
  0.00154410447630379), y = c(1.35172948829027, 0.59654026447333, 
  0.685835030118683, 0.741545898152761, 1.09653338596292, 0.119448208345102, 
  0.104092642854814), frame = c(200912, 201001, 201002, 201003, 
  201004, 201005, 201006)), .Names = c("x", "y", "frame"), row.names = c("1", 
  "2", "3", "4", "5", "6", "7"), class = "data.frame")
  </code></pre>
  
  <p>I've been able to get one plotted in a line, but it seems that it's not recognizing my frame as categorical (not that it is, nor do I know how to change it to such). </p>
  
  <pre><code>p &lt;- ggplot(df, aes(x=frame, y=x))
  p + geom_line()
  </code></pre>