title: How to create an edge list from a matrix in R?
body: <p>The relationship is expressed as a matrix <code>x</code> like this: </p>
  
  <pre><code>      A    B    C     D
  A     0    2    1     1
  B     2    0    1     0
  C     1    1    0     1
  D     1    0    1     0
  </code></pre>
  
  <p>The entries refer to the number of connections they have.</p>
  
  <p>Could anyone show me how to write it as an edge list?</p>
  
  <p>I would prefer to write it as an edge list:</p>
  
  <pre><code>A B
  A B
  A C
  A D
  B C
  </code></pre>
  
  <p>But would this edge list allow me to create a network plot?</p>