title: ValueError: Data is not binary and pos_label is not specified for roc_curve
body: <p>I'm trying to calculate roc_curve but I got this error message</p>
  
  <pre><code>Traceback (most recent call last):
    File "script.py", line 94, in &lt;module&gt;
      fpr, tpr, _ = roc_curve(y_validate, status[:,1])
    File "/usr/local/lib/python2.7/site-packages/sklearn/metrics/ranking.py", line 501, in roc_curve
      y_true, y_score, pos_label=pos_label, sample_weight=sample_weight)
    File "/usr/local/lib/python2.7/site-packages/sklearn/metrics/ranking.py", line 308, in _binary_clf_curve
      raise ValueError("Data is not binary and pos_label is not specified")
  ValueError: Data is not binary and pos_label is not specified
  </code></pre>
  
  <p>My code</p>
  
  <pre><code>status = rf.predict_proba(x_validate)
  fpr, tpr, _ = roc_curve(y_validate, status[:,1]) //error generated here
  roc_auc = auc(fpr, tpr)
  print roc_auc
  </code></pre>
  
  <p>P.S: Not really understand this solution (<a href="https://stackoverflow.com/questions/18401112/valueerror-data-is-not-binary-and-pos-label-is-not-specified">ValueError: Data is not binary and pos_label is not specified</a>) because it seems not really related.</p>