title: Gnuplot plot data from different files
body: <p>I'm looking for a way to plot data from different files into one graph.</p>
  
  <p>I'm testing different approaches to a problem. I have some parameters and I'm trying to conclude how the results are related to these parameters. I run some tests on the different solutions I'm comparing, and I redo this several times with different parameters.</p>
  
  <p>So I have several .csv files looking like this.</p>
  
  <pre><code>       test1    test2    test3    test4   ...
  sol1     1        1        1        1 
  sol2     1        1        1        1 
  sol3     1        1        1        1 
  sol4     1        1        1        1 
  ...
  </code></pre>
  
  <p>(These are of course filled with real data and not just 1's)</p>
  
  <p>I want to plot a graph where the Y axis is the result of (for example) test1/sol1 and the x axis plots the different parameter values (the different .csv files).</p>
  
  <p>I hope I have made clear what i'm trying to create.</p>
  
  <p>I am hoping there is a way of doing this directly in gnuplot. The file structure is this way in order to create some other graphs, so I don't really want to change it.</p>
  
  <p>I read about the possibility of concatenating two files, but i don't really see that of being much use here.</p>
  
  <p>EDIT: (thanks to Christoph) I want to plot the value in the cell test1/sol1 vs my parameter. The parameter is changing per file. So I need to read 1 datapoint per file.</p>
  
  <p>In the end I would like to plot this information for different solutions in one graph. So for the cells test1/sol1, test1/sol2, test1/sol3,... </p>
  
  <p>In the example below, the x axis would be the changing parameter, the Y axis would be the value in the corresponding cell from column 'test1' and the different lines correspond to the different solutions.</p>
  
  <p><a href="https://i.stack.imgur.com/HCxsz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HCxsz.png" alt="graph example"></a><br>
  <sub>(source: <a href="http://wiki.visvis.googlecode.com/hg/images/examples/example_plotting.png" rel="nofollow noreferrer">googlecode.com</a>)</sub>  </p>
  
  <p>(random image from google)</p>
  
  <p>I hope it's clearer now what I'm trying to achieve.</p>