title: D3 draw multiple files in one chart each file represent different line/bar
body: <p>I want to represent processors usage during a specific period of time, using D3.
  I have the data distributed in multiple files, all files have the same format, but each file represent different processor. eg:</p>
  
  <p><em>file1.tsv</em></p>
  
  <pre><code>time  P1
  t0    0
  t2    1
  t3    2
  </code></pre>
  
  <p><em>file2.tsv</em></p>
  
  <pre><code>time  P2
  t1    3
  t3    4
  t4    5
  </code></pre>
  
  <p>I want to draw these data in the same chart, each file data in separate line.
  The way D3 suggest in their tutorials to draw multi lines is to import all the processors in one file in such format:</p>
  
  <p><em>file-all-proc.tsv</em></p>
  
  <pre><code>time  P1  P2  P3
  t0    1   2   3
  t1    3   5   7 
  t2    1   3   5
  ..    .   .   .
  </code></pre>
  
  <p>Do you know if there is a better way to do it than manually merge my files? </p>
  
  <p>Manual merge will not be strait forward, as i should merge data, order them base on time, set zeros for empty fields, ...</p>