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Arraylist contains this number?  RSS feed

 
Greenhorn
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Hello people.
Srry for asking, but i've been trying for the last four hours and i'm not moving forward.

I'm programming this bingo thing. It has to check if a number exists in the arraylist. If it does, it should get a new number NytTal();

I've also tried with equals, but dosent seem to work either. I've made an system outprint;

[80, 11, 14, 14]
Equals: false
Contains: false


I've even tried with bought trukkettal and trukkettal2

what seems to be wrong here? i just have a simple arraylist and then some adds from actionperformed...

 
Bartender
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Your ArrayList is declared as containing String values but your if statement is checking if the ArrayList contains an Integer (the int value will be AutoBoxed to an Integer).
 
Marshal
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Welcome to the Ranch

I am afraid your five lines of code fill me with dread. And not about finding things in the List.
Why are you using a method which returns a String and parsing it to a number? Why did you not return a number?
Why are you trying to put things into a List, and then check whether they have already been added?
Why are you calling that code from a Listener? Why are you not developing it as a standalone application, which you will later wrap in a GUI? That is a far better way to develop applications. Your application should have an interface so you can do something like this:-I think there is a piece of hardware getting between you and the program. Unfortunately it is the computer, and I think you will have to put it aside. Instead, use a two‑dimensional carbohydrate‑based flexible writing surface¹.
Write down how you would do it is real life, with a bag of balls. See whether you can change the bag of balls to a Java collections implementation. I presume you are familiar with the random number methods in Java? (They are not really random, but you won’t notice the difference.)

¹ = sheet of paper
 
Bartender
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jonas sorensen wrote:It has to check if a number exists in the arraylist.

OK, but, as Tony said, that's NOT what you're doing.

Strings are NOT numbers. In fact, in your case (and many others) StringsAreBad (←click).

Winston
 
It is sorta covered in the JavaRanch Style Guide.
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