Java Linked List search

Question

I have a question regarding linked-lists. How would you search through one which looks like this and find the string "Freda"?

private LinkedList<Boat> boats = new LinkedList<Boat>();

boats.add(new Boat(1, "Ed", 3));

boats.add(new Boat(2, "Fred", 7));

boats.add(new Boat(3, "Freda", 5));

Iterate through the list, and for each boat compare the name. — Seelenvirtuose, Mar 18 '15 at 08:27
Better use [Map](http://docs.oracle.com/javase/7/docs/api/java/util/Map.html) if sole purpose is to search !!!! — Neeraj Jain, Mar 18 '15 at 08:27
Possible duplicate [http://stackoverflow.com/questions/5187888/java-searching-within-a-list-of-objects](http://stackoverflow.com/questions/5187888/java-searching-within-a-list-of-objects) — Flown, Mar 18 '15 at 08:31

score 0 · Answer 1 · answered Mar 18 '15 at 08:29

0

I assume, getName is the getter that will return the name of the boat.

for(int i=0;i<boats.size();i++){
  if(searchedWord.equals(boats.get(i).getName()){
   //do your operation here
  }
}

answered Mar 18 '15 at 08:29

Danyal Sandeelo

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score 0 · Answer 2 · answered Mar 18 '15 at 08:32

0

Itrate over your list and then search your value

for(Boat a: boats){
    if(a.name.equals("Freda")){ // name is the variable you have used to store "Fread" 
        //   sout("Found");
         break;
     }
}

answered Mar 18 '15 at 08:32

AJ.

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Isn't **Map** a preferrable approach for this kind of searching !! PS: [This clarifies what I am trying to say](http://stackoverflow.com/a/3770893/3143670) – Neeraj Jain Mar 18 '15 at 08:35

score 0 · Answer 3 · answered Mar 18 '15 at 08:38

Supposing that you have getters and setters on your Boat:

  public Boat search (LinkedList<Boat> list, String searchedName) {
      for (Boat boat : list) {
         if(boat.getName().equals(searchedName) {
               return boat;
                         }
                 }
     throw new IllegalArgumentExcetion("This boat was not found");
     }

score 0 · Answer 4 · answered Mar 18 '15 at 08:38

As already Added In comments your should opt for Map<Key,Value> Pair Approach

private Map<String,Boat> boats = new HashMap<String,Boat>();
boats.put("ED",new Boat(1, "Ed", 3));
boats.put("Fred",new Boat(2, "Fred", 5));
boats.put("Ted",new Boat(3, "Ted", 8));

Then when you want to search you can always do this way :

boats.get("Fred");

score 0 · Answer 5 · answered Jun 11 '18 at 21:49

If you want to search for stuff, you want to use an indexed collection like Data Store: https://github.com/jparams/data-store

Example:

Store<Boat> store = new MemoryStore<>() ;
store.add(new Boat(1, "Ed", 3));
store.add(new Boat(2, "Fred", 7));
store.add(new Boat(3, "Freda", 5));
store.index("name", Boat::getName);
Boat boat = store.getFirst("name", "Ed");

With data store you can create case-insensitive indexes and all sorts of cool stuff. If you are doing a lot of lookups, you definitely want to use a library like this over looping.

score 0 · Answer 6 · answered Jun 11 '18 at 22:01

0

You can solve it easily via filtering the list stream;

final List<Boat> ed = boats.stream().filter(boat -> boat.name.equals("Ed")).collect(Collectors.toList());

This will return a list of all the boats with name Ed

answered Jun 11 '18 at 22:01

fmatar

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Java Linked List search

6 Answers6