title: How to select two columns to plot with dataframe?
body: <p>apple is a dataframe whose data structure is as the below:</p>
  
  <pre><code>apple
             Date        Open        High         Low       Close   Adj Close  
  0    2017-01-03  115.800003  116.330002  114.760002  116.150002  114.311760   
  1    2017-01-04  115.849998  116.510002  115.750000  116.019997  114.183815   
  2    2017-01-05  115.919998  116.860001  115.809998  116.610001  114.764473   
  3    2017-01-06  116.779999  118.160004  116.470001  117.910004  116.043915   
  4    2017-01-09  117.949997  119.430000  117.940002  118.989998  117.106812   
  5    2017-01-10  118.769997  119.379997  118.300003  119.110001  117.224907   
  6    2017-01-11  118.739998  119.930000  118.599998  119.750000  117.854782   
  7    2017-01-12  118.900002  119.300003  118.209999  119.250000  117.362694   
  8    2017-01-13  119.110001  119.620003  118.809998  119.040001  117.156021   
  9    2017-01-17  118.339996  120.239998  118.220001  120.000000  118.100822 
  </code></pre>
  
  <p>Now i want to select two columns Date and Close ,to set Date as x axis and Close as y axis,how to plot it?</p>
  
  <pre><code>import pandas as pd    
  import matplotlib.pyplot as plt    
  x=pd.DataFrame({'key':apple['Date'],'data':apple['Close']})    
  x.plot()   
  plt.show() 
  </code></pre>
  
  <p>I got the graph such as below.</p>
  
  <p><a href="https://i.stack.imgur.com/1xc66.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1xc66.png" alt="enter image description here"></a></p>
  
  <p>The x axis is not Date column !    </p>