title: Convert Matrix to table in R
body: <p>I have a network graph as a matrix, loaded through a csv in R, and it counts the number of SMS messages between people. e.g:</p>
  
  <pre><code>NULL   john    mary    jim    bob    sue
  john   0       5       2      0      1
  mary   5       0       2      0      5
  jim    2       2       0      8      10
  bob    0       0       8      0      0
  sue    1       5       10     0      0
  </code></pre>
  
  <p>I want to transpose this for gephi into a table that works like this:</p>
  
  <pre><code>SOURCE    TARGET    WEIGHT
  john      mary      5
  john      jim       2
  john      bob       0
  john      sue       1
  mary      jim       2
  mary      bob       0
  mary      sue       5
  jim       bob       8
  jim       sue       10
  bob       sue       0
  </code></pre>
  
  <p>Then I can visualise and play with it as a network graph in gephi.</p>
  
  <p>Is there a quick R operation to use on the matrix ('m') to make it into the table and export it as another csv file?</p>
  
  <p>Thanks :)</p>