Counting in an ArrayList - Java

Question

UPDATED CODE

I'm trying to figure out a way to count how often one value appears in an ArrayList.

System.out.println("Hand 1, Number of Clubs: " 
              + hands[0].frequency(hands[0], Card.Suit.CLUBS));

So in the above case i want to count how many "Clubs" are in hands[0].

public int frequency(Hand c, Suit suit){
    int count = 0;
    if(suit == suit) //need this to be "If suit (club) is present, count++)
            {
             count++;
            }    
    return count;
}

I'm drawing a blank.... If i change the method type to ArrayList then i cannot return "count"

hands[0] is created by:

    Hand[] hands = new Hand[4];
    for(int i=0; i<hands.length; i++) {
       hands[i]=new Hand();
       }
       for(int i=0; i<=Deck.size()+8; i++) {
          for(Hand hand:hands) {
             hand.addSingleCard(Deck.deal());
           }
       }

It does compile. Although i have been playing around with it. hands[0] is an arrayList of cards (approximates 13 cards). I want to pass the method the hands[0] arrayList and possibly a suit and it return an int of how many of that suit is present in the arrayList. — binary101
– binary101, Commented Nov 15, 2012 at 15:05

Basil Bourque · Accepted Answer · 2019-03-28 01:15:16Z

3

`Collections.frequency`

You have this feature already available from Collections class, in the frequency method.

public static int frequency(Collection<?> c, Object o)

That will return the number of occurrences of a specific object inside a collection.

Mind that without providing a vaild equals method this won't work or at least won't work with the equality you have in mind, since Java does't know your meaning of equality.

edited Mar 28, 2019 at 1:15

Basil Bourque

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answered Nov 15, 2012 at 14:58

Jack

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1 Comment

binary101 Over a year ago

I've attempted to use your method, however it only returns 1 count... maybe i'm overlooking something simple...

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