Collection ...

Hello experts,

   I have the following file:
--------------------------
  Animal, Type
 
  turtle, reptile
  lizard, reptile
  snake, reptile
  dog, mammal
  cat, mammal
  rat, mammal
 shark, fish
 goldfish, fish
----------------------

   I want them in a structure like:
 
   reptile : turtle, lizard, snake
   mammal: dog, cat, rat
   fish : shark, goldfish

  What type of collection and structure should I use to solve this problem ? thanks.
 
LVL 1
meow00Asked:
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Jim CakalicSenior Developer/ArchitectCommented:
I'd probably approach this using a Map of Lists. You'd have a Map keyed by animal genus (or whatever it is) where the value of the map was a List which contained the species. Something like:

    Map genus = new HashMap();
    for each line in the file
        String split = line.split(",");
        List species = genus.get(split[0]);
        if (species == null) {
            species = new ArrayList();
            genus.put(split[0], species);
        }
        species.add(split[1]);

Regards,
Jim


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Jim CakalicSenior Developer/ArchitectCommented:
Hi, meow00. Did my comment answer your question?
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