title: python plt color label
body: <pre><code># x,y,size 데이터 셋팅
  x = target_data.accuracy
  y =  target_data.f1_score
  s = target_data.recall
  
  # 라벨셋팅(순서유의)
  users =['dnn', 'random forest', 'extra trees', 'ensemble']
  </code></pre>
  
  <p>This is a questionable point.</p>
  
  <pre><code># 컬러셋팅
  colors =  list(np.array([0.81520346,0.28735556, 0.6542928, 0.3542928]))
  df = pd.DataFrame(dict(accuracy=x, f1_score=y, users=users, s=s, c=colors ))
  
  # 그래프 그리기
  ax = df.plot.scatter(x='accuracy', y='f1_score', s=df.s*10,c= df.c,  alpha=0.5)
  for i, txt in enumerate(users):
      ax.annotate(txt, (df.accuracy.iat[i],df.f1_score.iat[i]))
  plt.show()
  </code></pre>
  
  <p>I definitely set the color array and matched the graph.</p>
  
  <p>The resulting image is well-formed with graphs and labels, but the color is represented as a black and white image.
  What's wrong?</p>