title: Unknown label type sklearn
body: <p>I 'm new in sklearn. I 'm trying to do this code</p>
  
  <pre><code>data = pandas.read_csv('titanic.csv')
  data= data[data['Pclass'].notnull() &amp; data['Sex'].notnull() &amp;         data['Age'].notnull() &amp; data['Fare'].notnull()]   
  test = data.loc[:,['Pclass','Sex','Age','Fare']]
  target = data.loc[:,['Survived']]
  test = test.replace(to_replace=['male','female'],value=[1,0])
  clf=DecisionTreeClassifier(random_state=241)
  clf.fit(target,test)
  </code></pre>
  
  <p>And I saw this error </p>
  
  <blockquote>
  <pre><code>ValueError: Unknown label type: array([[ 22.    ,   3.    ,   7.25  ,        1.    ],
     [ 38.    ,   1.    ,  71.2833,   0.    ],
     [ 26.    ,   3.    ,   7.925 ,   0.    ],
     ..., 
     [ 19.    ,   1.    ,  30.    ,   0.    ],
     [ 26.    ,   1.    ,  30.    ,   1.    ],
     [ 32.    ,   3.    ,   7.75  ,   1.    ]])
  </code></pre>
  </blockquote>
  
  <p>What is a problem?</p>