title: How to plot date and time in the y axis together
body: <p>So I have a data frame including 3 columns: 'Data', 'Date', 'Time'.
  I want to plot 'Data' on the x-axis and 'Date' and 'Time' together on the y-axis, since I have 24 values of time per every date value (1 value per hour). However, when I try to plot 'Time' on the x-axis, I get :</p>
  <pre><code>x = DF['Time']
  y=DF['Data']
  plt.plot(x,y)
  plt.xlabel('Data')
  plt.ylabel('NM data counts/hour')
  </code></pre>
  <p>TypeError: float() argument must be a string or a number, not 'datetime.time'</p>
  <p>On the other hand, when I try plotting 'Date' on the x-axis I do not have a single problem, you can see the plot on the link below.</p>
  <pre><code>x = DF['Date']
  y=DF['Data']
  plt.plot(x,y)
  plt.xlabel('Data')
  plt.ylabel('NM data counts/hour')
  </code></pre>
  <p><a href="https://i.stack.imgur.com/9X9uF.png" rel="nofollow noreferrer">You can see the plot here</a></p>
  <p><a href="https://i.stack.imgur.com/e4Qij.png" rel="nofollow noreferrer">The data frame looks like this</a></p>
  <p>The problem is that I have a lot of values per day, that is why I want to plot the 'Date' and 'Time' values together, to plot every Data point with its corresponding Time value. I hope that I am clear enough ):</p>
  <p>By the way, the data types are this:</p>
  <pre><code>DF=NM_data.loc[First_GMS_2011]
  DF.dtypes
  Date    datetime64[ns]
  Time            object
  Data             int64
  dtype: object
  </code></pre>
  <p>And the data frame looks like this:</p>
  <pre><code>           Date      Time    Data
  0    2011-01-01  00:00:00  825361
  1    2011-01-01  01:00:00  826873
  2    2011-01-01  02:00:00  824004
  3    2011-01-01  03:00:00  826001
  4    2011-01-01  04:00:00  823890
  ...         ...       ...     ...
  8721 2011-12-31  19:00:00  823309
  8722 2011-12-31  20:00:00  821926
  8723 2011-12-31  21:00:00  823056
  8724 2011-12-31  22:00:00  823263
  8725 2011-12-31  23:00:00  823552
  </code></pre>
  <p>Best regards!</p>