title: Plotting multiple columns of df using ggplot
body: <p>This question is similar to <a href="https://stackoverflow.com/questions/29193536/r-data-frame-of-lists-into-a-data-frame">r - data frame of lists into a data frame</a> but no answer was really sufficient.</p>
  
  <p>I have a <code>df</code> of time series data, comparing modeled to gage data. See below for a sub-section of the data: </p>
  
  <pre><code>Date        GageFlow  base0      1a       1b       2a        2b       3a       
  2003-10-01     78.6 72.43154 64.55318 64.55318 64.55318 64.55318 64.55318 
  2003-10-02     88.6 74.94789 68.48789 68.48789 68.48789 68.48789 68.48789 
  2003-10-03     96.6 75.08756 69.75530 69.75530 69.75530 69.75530 69.75530 
  2003-10-04     93.1 74.45323 66.67482 66.67482 66.67482 66.67482 66.67482 
  2003-10-05     90.2 72.89045 65.24120 65.24120 65.24120 65.24120 65.24120 
  2003-10-06     96.0 73.89078 67.88296 67.88296 67.88296 67.88296 67.88296 
  </code></pre>
  
  <p>The <code>str</code> of my data is:</p>
  
  <pre><code>'data.frame':   3653 obs. of  11 variables:
   $ Date    : Date, format: "2003-10-01" "2003-10-02" ...
   $ GageFlow: num  78.6 88.6 96.6 93.1 90.2 96 96 97.8 98.7 99.8 ...
   $ base0   :'data.frame':   3653 obs. of  1 variable:
    ..$ base0: num  72.4 74.9 75.1 74.5 72.9 ...
  </code></pre>
  
  <p>I would like to use <code>ggplot</code> to make a plot of the modeled scenarios with <code>geom_lines</code> of (<code>base0</code>, <code>1a</code>, <code>1b</code>, etc.) and <code>GageFlow</code>, with the <code>x-axis</code> as the <code>timeseries</code> (<code>x=Date</code>) provided.  The problem is that when I use <code>melt</code> to try and get this in a tall format, I receive an error: </p>
  
  <blockquote>
    <p>Error: Can't melt data.frames with non-atomic 'measure' columns
    In addition: Warning message:
    attributes are not identical across measure variables; they will be dropped </p>
  </blockquote>
  
  <p>Do I actually need to restructure my <code>df</code> or is there some way to <code>melt</code>, or use another function to produce such a plot. Of course I could do this the long way, but I'm trying to become more efficient.</p>
  
  <p>Thanks!</p>