title: Add category specific columns and values to dataframe
body: <p>I'm looking to create category-specific columns based the corresponding category for some of the columns.</p>
  
  <p>I've accomplished this in a round-about way by (1) slicing the 2 categories into two separate dataframes, (2) merging the two dataframes on the date (3) deleting redundant columns (4) creating new columns (category agnostic) (4) delete category specific columns. Do you know of a more efficient way to do this transfomration? My code is below the example input/output</p>
  
  <p>Input:</p>
  
  <pre><code>      wk start  car            rims color   Autopilot$  Sunroof$
  0   2018-09-09  tesla model x   17  black   3000         0
  1   2018-09-16  tesla model x   14  yellow  3000         0
  2   2018-09-23  tesla model x   13  white   3000         0
  3   2018-09-09  tesla model 3   19  grey    0            2000
  4   2018-09-16  tesla model 3   21  pink    0            2000
  </code></pre>
  
  <p>Ideal Output:</p>
  
  <pre><code>     wk       rims-mod3 rims-modx   color-mod3  color-modx  Auto$   roof$
  0   2018-09-09  17         0        black       grey        3000    2000
  1   2018-09-16  14         19       yellow      pink        3000    2000
  2   2018-09-23  13         21       white       NaN         3000    0
  </code></pre>
  
  <p>My code:</p>
  
  <pre><code>import pandas as pd
  df = pd.DataFrame({'wk start': ['2018-09-09', '2018-09-16', '2018-09-23','2018-09-09', '2018-09-16'], 
      'car': [ 'tesla model x', 'tesla model x', 'tesla model x','tesla model 3','tesla model 3'],
      'rims': [17,14,13,19,21],
      'color':['black','yellow','white','grey','pink'],
      'Autopilot$':[3000,3000, 3000,0,0],
      'Sunroof$':[0,0,0,2000,2000]})
  model3 = df[df['car']=='tesla model 3']
  modelx = df[df['car']=='tesla model x']
  example = model3.merge(modelx, how='outer',left_on='wk start',right_on='wk start',suffixes=('_model3', '_modelx'))
  del example['car_model3']
  del example['car_modelx']
  example['AUTOPILOT']=example['Autopilot$_model3']+example['Autopilot$_modelx']
  example['SUNROOF']=example['Sunroof$_model3']+example['Sunroof$_modelx']
  del example['Autopilot$_model3']
  del example['Autopilot$_modelx']
  del example['Sunroof$_modelx']
  del example['Sunroof$_model3']
  </code></pre>
  
  <p>Other resources used are <a href="https://stackoverflow.com/questions/48667118/pandas-groupby-each-column-and-add-new-column-for-each-group">question1</a>, <a href="https://stackoverflow.com/questions/46942587/create-new-column-from-specific-rows-in-pandas-dataframe">question2</a></p>