title: Pandas: replace a single column (field) of strings with one column for each string
body: <p>Say I have the following dataframe:</p>
  
  <pre><code>    Colors                  
  0   red, white, blue
  1   white, blue
  2   blue, red
  3   white
  4   blue
  </code></pre>
  
  <p>where each unique value in column "Colors" needs to become an individual column, so that these columns can be populated with Boolean indices. Example:</p>
  
  <pre><code>    red white blue white,blue blue,red red,white,blue                    
  0   0   0     0    0          0        1    
  1   0   0     0    1          0        0
  2   0   0     0    0          1        0
  3   0   1     0    0          0        0
  4   0   0     1    0          0        0
  </code></pre>
  
  <p>Looking for suggestions on how to deal with this</p>