title: subtract two columns of different Dataframe with python
body: <p>I have two DataFrames, df1:</p>
  
  <pre><code>     Lat1         Lon1     tp1
  0   34.475000  349.835000   1
  1   34.476920  349.862065   0.5
  2   34.478833  349.889131   0
  3   34.480739  349.916199   3
  4   34.482639  349.943268   0
  5   34.484532  349.970338   0
  </code></pre>
  
  <p>and df2:</p>
  
  <pre><code>      Lat2         Lon2    tp2
  0   34.475000  349.835000   2
  1   34.476920  349.862065   1
  2   34.478833  349.889131   0
  3   34.480739  349.916199   6
  4   34.482639  349.943268   0
  5   34.484532  349.970338   0
  </code></pre>
  
  <p>I want to substract (tp1-tp2) columns and create a new dataframe whose colums are Lat1,lon1,tp1-tp2. anyone know how can I do it? </p>