title: sklearn Perceptron learning
body: <p>I'm trying to understand how Perceptron from sklearn.linear_model performs fit() function (<a href="http://scikit-learn.org/stable/modules/generated/sklearn.linear_model.Perceptron.html#sklearn.linear_model.Perceptron.fit" rel="nofollow">Documentation</a>). Question comes from this piece of code:</p>
  
  <pre><code>clf = Perceptron()
  clf.fit(train_data, train_answers)
  
  print('accuracy:', clf.score(train_data, train_answers))
  accuracy: 0.7
  </code></pre>
  
  <p>I thought goal of fitting is to create classification function which will give answer with 100% accuracy on test data, but in the example above it gives only 70%. I have tried one more data set where accuracy was 60%. </p>
  
  <p>What do I misunderstand in fitting process?</p>