Solved

list iterator

Posted on 2008-06-23
6
167 Views
Last Modified: 2010-03-30
Hi,

I use iterators with maps pretty often like:

    for (Map.Entry<Integer, String> it: mylist.entrySet()) {
       it.getValue().toString();
    }

how do you do the same with an ArrayList?

Thanks
0
Comment
Question by:DJ_AM_Juicebox
  • 2
  • 2
  • 2
6 Comments
 
LVL 86

Accepted Solution

by:
CEHJ earned 250 total points
ID: 21850253
for (T t : someList)

(where 'T' is the type)
0
 
LVL 92

Expert Comment

by:objects
ID: 21851250
Heres an example:

ArrayList<String> list = new ArrayList<String>();

for (String s : list}
{
    System.out.println(s);
}

0
 

Author Comment

by:DJ_AM_Juicebox
ID: 21862528
Quick question on that, consider:

public class Test
{
    ArrayList<Car> m_cars;

    public ArrayList<Car> getCars()
    {
        return m_cars;
    }
}

public static void main()
{
    Test test = new Test();

    for (Car car : test.getCars())
    {
         ....
    }
}

every time an iteration of the for-loop is done, does it need to call getCars() for any reason? I'm comparing that to:

    for (int i = 0; i < test.getCars().size(); i++) {
          ...
    }

where it would have to call getCars() every iteration.

Thanks
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 92

Assisted Solution

by:objects
objects earned 250 total points
ID: 21862560
no it wouldn't (it would use iterator)

>     public ArrayList<Car> getCars()

on a side note, making it return List instead of ArrayList is generally abetter idea.
Allows you to change the List implementation used in your class in the future without affecting users of the class.

    public List<Car> getCars()

0
 

Author Comment

by:DJ_AM_Juicebox
ID: 21862574
ok thanks
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 21864147
:-)
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
spring jars download 1 52
runtime exception 2 50
Delphi Firemonkey: if the Sms contain special characters it won't send it 3 62
jsp error 6 42
An old method to applying the Singleton pattern in your Java code is to check if a static instance, defined in the same class that needs to be instantiated once and only once, is null and then create a new instance; otherwise, the pre-existing insta…
By the end of 1980s, object oriented programming using languages like C++, Simula69 and ObjectPascal gained momentum. It looked like programmers finally found the perfect language. C++ successfully combined the object oriented principles of Simula w…
Viewers learn about the third conditional statement “else if” and use it in an example program. Then additional information about conditional statements is provided, covering the topic thoroughly. Viewers learn about the third conditional statement …
Viewers will learn about the different types of variables in Java and how to declare them. Decide the type of variable desired: Put the keyword corresponding to the type of variable in front of the variable name: Use the equal sign to assign a v…

685 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question