title: Parsing out file - specific issue
body: <p>I have been given a student problem as I am learning python in school. I am struggling a bit to think of ways to solve it. This is an example of the file that I have to parse out: </p>
  
  <pre><code>cupboard_blue “a”   drawer1       -1 
  cupboard_blue “a”   drawer2       -1
  cupboard_blue “a”   drawer3       -1 
  cupboard_blue “a”   drawer4       -1  
  cupboard_blue “b”   drawer1       -1  
  cupboard_blue “b”   drawer2       apple 
  cupboard_blue “b”   drawer3       -1  
  cupboard_blue “b”   drawer4       -1  
  
  cupboard_yellow “a” drawer1       -1 
  cupboard_yellow “a” drawer2       -1
  cupboard_yellow “a” drawer3       -1 
  cupboard_yellow “b” drawer1       -1 
  cupboard_yellow “b” drawer2       lychee  
  cupboard_yellow “b” drawer3       -1 
  
  cupboard_red  “a”   drawer1       pear 
  cupboard_red  “a”   drawer2       pear 
  cupboard_red  “b”   drawer1       pear 
  cupboard_red  “b”   drawer2       pear
  </code></pre>
  
  <p>There are different colour categories of cupboards - in the example above there are red, yellow, and blue cupboards. Each colour has two different cupboards ‘a’ and ‘b’ - i.e. 2 blue cupboards and 2 red cupboards in total. 
  Each cupboard has drawers that may be empty or full of fruit. </p>
  
  <p>I want to write a script where I parse out only the colour types where all cupboards in that category have all drawers that are full of fruit. So in the example above the output would be:  </p>
  
  <pre><code>cupboard_red  “a”   drawer1       pear 
  cupboard_red  “a”   drawer2       pear 
  cupboard_red  “b”   drawer1       pear 
  cupboard_red  “b”   drawer2       pear 
  </code></pre>
  
  <p>I would really appreciate some guidance on this problem. I hope it makes sense. </p>