title: why does my networkx graph display no edges between the nodes?
body: <p>I have two lists. One of them has this data structure: in each row first element is the ID, second is the email adress.</p>
  
  <pre><code>     ['0', 'kvogel@politico.com']
       ['1','ababab@politico.com']
  </code></pre>
  
  <p>the Second list is a "who wrote to whom" list, in each row with the first ID-Number being the sender and the second being the recipient</p>
  
  <pre><code>     ['0', '4']
       ['0', '6']
       ['1', '4']
  </code></pre>
  
  <p>Btw, the brackets are not actually part of the lists. this is my jupyter notebook output. the first list has around 2000 and the second list has 40000 rows. In the code below i add the nodes - in this case the email adresses - from the first list. and then i loop through the second list and use the given IDs to create edges between the nodes.</p>
  
  <pre><code>    first =-1
      second =-1
      for row in idsList:
           g.add_nodes_from(row[1])
      for row in dncList:
          for i in range (len(idsList)):
              if (row[0]==idsList[i][0]):
                  first=i;
              elif(row[1]==idsList[i][0]):
                  second=i
          g.add_edge(idsList[first][1],idsList[second][1])
      nx.draw_networkx(g,with_labels = False, node_size = 30)
      plt.show()
  </code></pre>
  
  <p>However, i can't see the edges between the nodes. the above code produces the below graph. printing with <code>edges()</code> gives me the list of all the edges, so no problem there. what am i missing here?</p>
  
  <p><a href="https://i.stack.imgur.com/iD9um.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iD9um.png" alt="Graph"></a></p>