title: Association between products or cross sell %
body: <p>I have a table like </p>
  
  <pre><code>ID     ProductBought
  1       A
  1       B
  1       C
  2       A
  1       B
  2       C
  3       B
  3       C
  2       D
  3       D
  4       A
  4       B 
  4       C
  </code></pre>
  
  <p>I intend to calculate : 
  Bought A , also bought B - 2 cases (  ID 1 and 4 ) , overall  = 2/3 IDs ( 3 IDs bought A of which 2 bought B ) </p>
  
  <p>i know this would be related to association rules/apriori but i want overall aggregated numbers/calculations for all possible product combinations , below is illustration for the kind of table output m looking at :</p>
  
  <pre><code>Category  Total distinct customer( in LHS )     % cross sell
  A to B        3                                     66% 
  A to C        3                                     66 % 
  B to C        3                                     100 %
  </code></pre>